JP2010012574A - Micromechanical structure and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To expand the rockable angle of a reflecting surface by elevating the fixing portion in a micromechanical structure, in which movable beams extending from the fixing portion support the reflecting surface. <P>SOLUTION: The micromechanical structure, formed by removing the sacrificial etch layer, includes a substrate 42, a fixing portion 113 vertically raised from the substrate, movable beams 112a and 112b connected to the fixing portion and extended parallel to the substrate at the height of a gap H away from the substrate, a rocking plate 111 connected to the distal end of the movable plate and the angle between which and the substrate varies, and a reflecting surface 161 formed on the surface of the rocking plate. The width L of the fixing portion 131 measured toward the extending direction of the movable beams 112a and 112b is larger than the thickness T of the movable beams 112a and 112b measured perpendicularly to the substrate 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a micromechanical structure and a manufacturing method thereof.

Micro Electro Mechanical Systems (MEMS) with a three-dimensional structure can be manufactured using semiconductor integrated circuit fabrication technology, and include pressure sensors, acceleration sensors, gyroscopes, or digital micromirrors. A device (hereinafter referred to as DMD) or the like is realized. In order to realize a three-dimensional structure with a semiconductor integrated circuit manufacturing technique, a technique of selectively and locally etching a laminated board including a sacrificial etching layer is used.
The micro mechanical structure (hereinafter referred to as MEMS) in the present invention uses a semiconductor integrated circuit manufacturing technique represented by a film forming technique and an etching technique, and selectively and locally a laminated board including a sacrificial etching layer. A three-dimensional structure realized by etching.

  Some MEMS that realize sensors, DMDs, and the like include a substrate, a fixed portion, a movable beam, and a swing plate. The fixed part rises vertically from the substrate. The movable beam is connected to the fixed portion and extends in parallel with the substrate at a height spaced from the substrate. The swing plate is connected to the tip of the movable beam, and the angle formed with the substrate changes. The MEMS realizing the DMD includes an actuator that swings the swing plate, and the swing plate swings with respect to the substrate by deforming the movable beam. In the case of a MEMS that realizes a sensor, when an external force is applied, the swing plate swings with respect to the substrate by deforming the movable beam. By detecting the swing angle of the swing plate, it is possible to detect the applied external force and the like.

The above MEMS are disclosed in Patent Document 1 and Patent Document 2.
JP-A-8-146911 Japanese Patent Laid-Open No. 2005-221903

  There is a demand for a MEMS having a movable beam and a swing plate to increase the swingable angle of the swing plate. For example, if the oscillating angle of the MEMS oscillating plate that realizes DMD can be increased, the reflection direction of the light beam can be changed greatly, and the light beam can be incident on the large aperture lens or not. Therefore, a bright image can be realized using a large aperture lens.

A MEMS having a substrate, a fixed portion, a movable beam, and a swing plate is formed using a sacrificial etching layer. That is, a sacrificial etching layer having the same gap thickness is prepared in order to secure a gap between the substrate and the movable beam and a gap between the substrate and the swing plate. Side surfaces are formed in the sacrificial etching layer, and fixed portions are formed using the side surfaces.
Specifically, as shown in FIG. 70, a laminated plate in which a supporting plate 602, a supporting plate surface etching resistant layer 604, and a sacrificial etching layer 606 are laminated is prepared. The support plate 602 and the support plate surface etching resistant layer 604 are collectively referred to as a substrate 600. The thickness of the sacrificial etching layer 606 is adjusted to H. In the sacrificial etching layer 606, a side surface 606a is formed at a site where the fixing portion 616 will be manufactured later. Next, as shown in FIG. 71, an inner etching resistant layer 608, an easy etching layer 610, and an outer etching resistant layer 612 are laminated. The inner etching resistant layer 608, the easy etching layer 610, and the outer etching resistant layer 612 are formed not only on the surface of the sacrificial etching layer 606 but also on the side surface 606a. Note that the easy-etching layer 610 is removed in the formation range of a through hole 614 described later. Next, as shown in FIG. 72, a through hole 614 that penetrates the outer etching resistant layer 612 and the inner etching resistant layer 608 and reaches the sacrificial etching layer 606 is formed. The through hole 614 is formed in a range where the easy-etching layer 610 is removed. Next, as shown in FIG. 73, the sacrificial etching layer 606 is removed by etching from the through hole 614. In order to protect the support plate 602 with the support plate surface etching resistant layer 604 and to etch the easy etching layer 610 with the inner etching resistant layer 608 and the outer etching resistant layer 610, the supporting plate 602 and the easy etching layer 610 are Only the sacrificial etching layer 606 is etched without being etched. FIG. 74 shows a plan view of the MEMS obtained at this stage.
As a result, as shown in FIGS. 73 and 74, the fixed portion 616, the movable beam 618, and the swing plate 620 are formed on the substrate 600. The fixing portion 616 stands up from the surface of the substrate 600 in the vertical direction. The movable beam 618 is connected to the fixed portion 616 and extends in parallel with the substrate 600 at a height separating the gap H (equal to the thickness H of the sacrificial etching layer 606) from the substrate 600. The swing plate 620 continues to the tip of the movable beam 618, and the angle formed with the substrate 600 changes when the movable beam 618 is deformed. The movable beam 618 is formed with a narrow width W so as to be easily deformed.

The easy-etching layer 610 is conductive. When the MEMS is an active type such as DMD, the easy-etching layer 610 that constitutes a part of the swing plate 620 constitutes an actuator that applies a voltage or the like. When the MEMS is a passive type such as a sensor, an easy-etching layer 610 constituting a part of the swing plate 620 constitutes an electrode that changes an output voltage or the like when the swing plate 620 swings.
The conductive easy etching layer 610 constituting the fixing portion 616 includes an easy etching layer 610 constituting a part of the swing plate 620 and a conductive layer (not shown) formed on the surface of the substrate 600. Connect electrically.

  The above is a normal method for forming the fixed portion 616, the movable beam 618, and the swing plate 620. The fixed portion 616, the movable beam 618, and the swing plate 620 are all formed in the inner etching resistant layer 608 and the easy etching layer 610. And an outer etching resistant layer 612. The width L of the fixed portion 616 measured in the direction in which the movable beam 618 extends is substantially equal to the thickness T of the movable beam 618 measured in the direction perpendicular to the substrate 600.

When the gap H between the substrate 600 and the movable beam 618 or the gap H between the substrate 600 and the swing plate 620 is small, no particular inconvenience occurs in the MEMS manufactured by the above method.
However, in order to increase the swingable angle of the swing plate 620, the gap H between the substrate 600 and the movable beam 618 or the gap H between the substrate 600 and the swing plate 620 must be increased. When the gap H is increased, a serious problem occurs.
One problem is that when the gap H becomes larger, the strength of the fixing portion 616 becomes insufficient, and the fixing portion 616 deforms against the intention, so that the intended gap H cannot be secured. Since the gap H directly affects the characteristics of the MEMS, the intended characteristics cannot be obtained unless the intended gap H can be secured. Increasing the thickness of the inner etching resistant layer 608, the easy etching layer 610 or the outer etching resistant layer 612 can improve the strength of the fixed portion 616, but this time the rigidity of the movable beam 618 becomes too high, and the swing plate It becomes difficult to swing 620. Increasing the strength of the fixed portion 616 and securing the flexibility of the movable beam 618 are in a trade-off relationship, and it is difficult to satisfy both at the same time.
Another problem is that when the gap H is increased, the conductive easy-etching layer 610 that passes through the fixing portion 616 is easily disconnected.

One object of the present invention is to increase the strength of the fixed portion and maintain the flexibility of the movable beam in a structure in which the movable beam and the swing plate are supported at a height spaced from the substrate by the fixed portion. The technology that realizes both of them simultaneously is provided.
A further object of the present invention is to provide a technique for preventing disconnection of a conductive layer passing through a fixed portion in the above structure.

The present invention realizes a novel micromechanical structure (MEMS). The MEMS here refers to an object having a three-dimensional structure obtained by locally removing a specific layer among the layers constituting the laminated plate.
The MEMS of the present invention includes a substrate, a fixed portion rising in a vertical direction from the substrate, a movable beam connected to the fixed portion and extending in parallel to the substrate with a gap from the substrate, and a movable beam And an oscillating plate whose angle with the substrate changes. The MEMS of the present invention is characterized in that the width of the fixed portion measured in the direction in which the movable beam extends is larger than the thickness of the movable beam measured in the direction perpendicular to the substrate.

As described in the problem section, in the MEMS manufactured by the conventional method, the width of the fixed portion measured in the direction in which the movable beam extends is equal to the thickness of the movable beam measured in the direction perpendicular to the substrate. For this reason, if the gap between the substrate and the movable beam or the gap between the substrate and the swing plate is increased, the strength of the fixed portion is insufficient and the gap cannot be maintained. If the width of the fixed portion is increased, the strength of the fixed portion can be ensured, but this time the movable beam is difficult to deform. Since it is necessary to ensure the mobility of the movable beam, it is not possible to employ a structure that increases the width of the fixed portion to ensure the strength of the fixed portion.
The MEMS of the present invention has achieved the result that the width of the fixed part measured in the direction in which the movable beam extends is larger than the thickness of the movable beam measured in the direction perpendicular to the substrate by improving the manufacturing method. Yes.
According to the MEMS having the above relationship, it is possible to increase the strength of the fixed portion and simultaneously maintain the flexibility of the movable beam. While maintaining the flexibility of the movable beam, the gap between the substrate and the movable beam or the gap between the substrate and the swing plate can be increased, and the swingable angle of the swing plate can be increased.

In order to change the width of the fixed part and the thickness of the movable beam, it is preferable to change the laminated structure constituting the fixed part and the laminated structure constituting the movable beam. For example, the movable beam and the swing plate adopt a structure in which an inner etching resistant layer, an easy etching layer, and an outer etching resistant layer are observed in order from the substrate side when observed in a cross section perpendicular to the substrate. As for the fixed part, an additional etching resistant layer and an additional easy etching layer are observed in order from the side of the movable beam when observed in a cross section along the direction in which the movable beam extends while being perpendicular to the substrate. It is preferable to adopt a structure.
The additional easy etching layer may be formed of the same material as the sacrificial etching layer used in the MEMS manufacturing process. The etching resistant layer mentioned above means having resistance to an etching agent that etches the sacrificial etching layer, and means a layer that remains after the sacrificial etching layer is removed by etching. The easy-etching layer means that the etching rate by the etching agent for etching the sacrificial etching layer is high, and it disappears when the sacrificial etching layer is etched unless it is covered with the etching-resistant layer. . Furthermore, “addition” here indicates a layer that is not found in the stack constituting the movable beam and the swing plate.

  When the fixed part is formed by a structure in which an additional etching resistant layer and an additional easy etching layer are observed in order from the movable beam side when observed in a cross section along the direction in which the movable beam extends, the flexibility of the movable beam Irrespective of this, the strength of the fixed part can be freely adjusted.

A normal etching resistant layer is formed of an insulating material, and a normal easy etching layer is often formed of a conductive material.
In this case, the easy-etching layer constituting the movable beam and the additional easy-etching layer constituting the fixed part are passed through the holes formed in the inner etching-resistant layer located between the movable beam and the fixed part. A conducting structure can be realized.

  According to said structure, the additional easy etching layer which comprises the fixed part functions also as a conductor which connects the easy etching layer which comprises the movable beam, and the conductive layer currently formed in the board | substrate. Even if the fixed portion is raised and the gap between the movable beam and the substrate is increased, it is possible to prevent the occurrence of an accident in which the conductor passing through the fixed portion is disconnected.

According to the present invention, since the strength of the fixing portion can be increased, the height can be increased. That is, it is possible to realize a relationship in which the height of the fixed portion measured in the direction perpendicular to the substrate is larger than the width of the fixed portion measured in the direction in which the movable beam extends.
In this case, the gap between the swing plate and the substrate can be increased to ensure a sufficient swingable angle of the swing plate.

  The MEMS of the present invention is suitable for forming a plurality of unit structures on a common substrate, where a unit composed of a fixed portion, a movable beam, and a swing plate is used as a unit. That is, a structure in which a plurality of unit structures are arranged on a common substrate can be easily realized.

  According to the above, it is possible to realize a MEMS in which a plurality of swing plates are arranged. For example, an image creating apparatus configured by regularly arranging a plurality of swing plates can be realized.

  When realizing an image creating apparatus, it is preferable to form a reflecting surface on the outer surface of each swing plate. By forming the reflection surface, it is possible to secure a reflected light amount and form a bright image.

The MEMS of the present invention can be manufactured by the following manufacturing method. In this manufacturing method, a MEMS is manufactured by selectively and locally etching a laminate including a gap forming layer, a part of which is a sacrificial etching layer. The range of the gap forming layer that is removed by etching is referred to as a sacrificial etching layer.
In this manufacturing method, a laminated plate is prepared in which a supporting plate, a supporting plate surface etching resistant layer, a gap forming layer, an inner etching resistant layer, an easy etching layer, and an outer etching resistant layer are laminated.
In this laminated plate, an additional etching resistant layer that penetrates the gap forming layer is formed at a position where the fixed portion faces a gap located inside the movable beam. In addition, a gap forming layer serving as an additional easy etching layer forming a part of the fixed portion is surrounded by the additional etching resistant layer and the outer etching resistant layer.
In this manufacturing method, the laminated plate is etched. At this time, the support plate surface is protected by the etching resistant layer, and the additional etching resistant layer and the outer etching resistant layer protect the gap forming layer which forms an additional easy etching layer constituting a part of the fixed portion, and the inner etching resistant property. The sacrificial etching layer is etched with the easy etching layer protected by the layer and the outer etching resistant layer. That is, the gap forming layer not protected by the etching resistant layer is removed by etching.
As a result, the sacrificial etching layer existing between the substrate and the movable beam and between the substrate and the swing plate is removed, and a gap is formed between the substrate and the movable beam and between the substrate and the swing plate.
In the portion where the fixing portion is formed, the gap forming layer is surrounded by the additional etching resistant layer and the outer etching resistant layer. Therefore, the gap forming layer in the surrounded range remains without being etched. Thereby, a part of the fixing portion is formed.
According to this method, it is possible to form a fixing portion having high strength.

According to the present invention, in a micromechanical structure including a substrate and a movable beam extending in parallel to the substrate at a distance from the substrate, the strength of the fixed portion that fixes the movable beam to the substrate is increased. Can do. That is, the width of the fixed portion measured in the direction in which the movable beam extends can be made larger than the thickness of the movable beam measured in the direction perpendicular to the substrate, and the thin movable beam can be supported by the thick fixed portion. . The gap between the substrate and the movable beam can be increased by using a high fixed portion, and the swingable angle of the swing plate can be increased.
When the movable beam is formed by a laminated structure of the inner etching resistant layer, the easy etching layer, and the outer etching resistant layer, the fixed portion can be formed by the additional etching resistant layer and the additional easy etching layer. In this case, the width of the additional easy etching layer (the distance measured in the direction in which the movable beam extends) can be freely adjusted, and the thickness of the fixed portion can be freely adjusted.
The additional easy-etching layer that forms the fixing portion can also be formed of a conductor. In this case, the additional easy-etching layer can be used as a part of the wiring. Even if the gap between the substrate and the movable beam is increased, the wiring does not break.
The micromechanical structure of the present invention can realize a structure in which a plurality of micromechanical structures are arranged on a common substrate by using a sacrificial etching layer. In this case, an image forming apparatus that provides a bright image can be configured by forming a reflecting surface on the outer surface of each swing plate.

In the best mode of the present invention, a micromechanical structure is manufactured using a silicon substrate (support plate). Polycrystalline silicon is used for the sacrificial etching layer or the easy etching layer, and silicon oxide or silicon nitride is used for the etching resistant layer.
In the best mode of the present invention, the fixed portion is formed by leaving a part of the gap forming layer protected from etching.
In the best mode of the present invention, polycrystalline silicon is used for the gap forming layer, and polycrystalline silicon forming the fixed portion is used for a part of the wiring.
In the best mode of the present invention, an electrode pair is provided between the swing plate and the substrate, and the swing plate is swung by exerting an attractive force between the electrode pair.
In one embodiment of the present invention, both sides of the swing plate are supported by a torsion beam.
In another embodiment of the present invention, a pair of slits are provided in the vicinity of the center of the swing plate, and the inner part of the slits is used as a movable beam.

The features of the preferred embodiment are listed first.
(Feature 1) The movable beam is formed of a laminated structure of a silicon thermal oxide film, a polycrystalline silicon layer, and a silicon thermal oxide film.
(Feature 2) When the fixed portion is observed in the height direction, it is formed of a laminated structure of a thermal oxide film formed on the surface of the silicon substrate, a polycrystalline silicon layer, and a silicon thermal oxide film. The thermal oxide film of silicon is also a thermal oxide film of silicon forming the inner etching resistant layer of the movable beam.
(Feature 3) A wiring portion into which impurities are implanted is formed in the vicinity of the surface of the silicon substrate. An opening is formed in the thermal oxide film formed on the surface of the silicon substrate, and the polycrystalline silicon layer forming the fixing portion is electrically connected to the wiring portion formed in the vicinity of the surface of the silicon substrate.
(Characteristic 4) A polycrystalline silicon layer in which an opening is formed in the silicon thermal oxide film forming the inner etching resistant layer of the movable beam and forming a fixed portion, and a polycrystalline silicon layer in which the movable beam is formed Is conducting.
(Characteristic 5) A fixed portion is formed in the vicinity of the center of the swing plate. A movable beam extends from the fixed portion to both sides, and the swing plate is connected to the tips of the pair of movable beams. In other words, a pair of slits are formed in the vicinity of the center of the swing plate, and a movable beam is formed between the pair of slits. The fixing part is disposed between the pair of slits.
(Feature 6) A recess is formed in the substrate, and the movable range of the swing plate is expanded.
(Characteristic 7) A film that alleviates an impact when the swing plate collides with the substrate extends from the boundary between the substrate and the recess.

(First embodiment)
1 shows a plan view of the micromechanical structure 200 of the first embodiment, FIG. 2 shows a cross-sectional view taken along line EF in FIG. 1, and FIG. 3 shows a cross-sectional view taken along line GH in FIG. Show. For the sake of understanding, FIG. 1 shows a plan view at various heights superimposed, and not all members are visually recognized at the same height. FIGS. 1 to 3 show only one micro mechanical structure 200, but actually, as shown in FIGS. 68 and 69, a large number of micro mechanical structures 200 are formed on the common substrate 10. FIG. They are arranged in a matrix. A reflective surface 161 is formed on the upper surface of each micromechanical structure 200. In FIG. 68, each reflecting surface 161 can swing in the direction connecting Y and Z. Around the area where the plurality of micromechanical structures 200 are arranged, a drive circuit 500 that adjusts the voltage applied to the electrode pair provided for each micromechanical structure 200 is provided. The drive circuit 500 can adjust the voltage applied to the electrode pair independently from the other electrode pairs. By the arrangement of the drive circuit 500 and the micromechanical structure 200 arranged in a matrix, an image display device that provides an image by switching light and dark for each cell is realized.

  As shown in FIGS. 1 and 2, the micromechanical structure 200 as a unit is formed on the surface of a substrate 42 composed of a single crystal silicon substrate 10 (support plate) and a thermal oxide film 40 covering the surface. And a fixed portion 113, a pair of torsion beams (movable beams) 112 a and 112 b, and a swing plate 111. The pair of torsion beams 112 a and 112 b and the swing plate 111 are positioned at a height with a gap from the substrate 42. A reflective surface 161 is provided on the surface of the swing plate 111. A pair of electrodes 20 a and 20 b are provided on the surface of the single crystal silicon substrate 10 located below the swing plate 111. The electrode 20a is disposed at a position above the line segment connecting the pair of torsion beams 112a and 112b in FIG. 1, and the electrode 20b is below the line segment connecting the pair of torsion beams 112a and 112b in FIG. It is arranged at the position. When the voltage applied to the pair of electrodes 20a and 20b is changed, the oscillating plate 111 and the reflecting surface 161 oscillate around the line segment connecting the pair of torsion beams 112a and 112b, and the light beam incident on the reflecting surface 161 is obtained. Change the reflection direction.

  As shown in FIG. 2, the fixing portion 113 extends vertically (in the height direction) from the substrate 42, and extends on the surface of the substrate 42 along a square side as shown in FIG. 1. The pair of torsion beams 112 a and 112 b are supported by the fixing portion 113 and extend parallel to the substrate 42 at a height separated from the substrate 42 by a gap H. The swinging plate 111 is connected to the tip of each of the pair of torsion beams 112a and 112b, and extends at a height separated from the substrate 42 by a gap H. The swinging plate 111 swings around a straight line connecting the pair of torsion beams (movable beams) 112a and 112b by the attractive force applied by the electrodes 20a and 20b to the swinging plate 111.

Diffusion layers processed to have conductivity by impurity diffusion are formed in various ranges on the surface of the silicon substrate 10, and the first fixed electrode 20a, the first fixed electrode wiring 21a, A second fixed electrode 20b, a second fixed electrode wiring 21b, and a movable electrode wiring 30 are formed. The surface of the silicon substrate 10 is covered with a first insulating film 40 on which a contact window described later is formed.
The first fixed electrode 20a is connected to the first fixed electrode via the first fixed electrode wiring 21a, the first fixed electrode contact 140a (contact window formed in the first insulating film 40), and the first fixed electrode terminal 150a. Connected to the portion 151a. The second fixed electrode 20b is connected to the second fixed electrode via the second fixed electrode wiring 21b, the second fixed electrode contact 140b (contact window formed in the first insulating film 40), and the second fixed electrode terminal 150b. Connected to the portion 151b. The movable electrode wiring 30 is connected to the movable electrode connection portion 151c via the first movable electrode contact 130 (contact window formed in the first insulating film 40) and the movable electrode terminal 150c. Each of the first fixed electrode terminal 150a, the second fixed electrode terminal 150b, and the movable electrode terminal 150c is made of aluminum. The first fixed electrode terminal 150a is protected by a first fixed electrode terminal protective film 152a. The second fixed electrode terminal 150b is protected by a second fixed electrode terminal protective film 152b. The movable electrode terminal 150c is protected by a movable electrode terminal protective film 152c. The first fixed electrode terminal 150a, the second fixed electrode terminal 150b, and the movable electrode terminal 150c are protected by an electrode terminal protective film 152 formed of an oxide film. The first fixed electrode connection portion 151a is exposed from the first fixed electrode terminal protective film 152a, and the second fixed electrode connection portion 151b is exposed from the second fixed electrode terminal protective film 152b, and the movable electrode connection portion 151c. Is exposed from the movable electrode terminal protective film 152c.

As shown in FIG. 2, when the cross section of the fixing portion 113 is observed from the inside to the outside, that is, when observed from the side where the torsion beams 112a and 112b are present to the non-existing side, it is formed of SiO ₂ . An etching resistant film (additional etching resistant film) 71, a fixing member (additional easy etching layer) 62 made of polycrystalline silicon, and a second insulating film (inner etching resistant film) 90 made of SiO ₂ , A laminated structure of the third insulating film (outer etching resistant film) 120 formed of SiO ₂ is observed. The width of the fixing member 62 measured along the direction in which the pair of torsion beams (movable beams) 112a and 112b extends is sufficiently thick, and the strength or rigidity of the fixing portion 113 is high. The fixed member 62 made of polycrystalline silicon is treated so as to have conductivity, and the movable electrode wiring 30 is provided via the second movable electrode contact 50 (contact window formed in the first insulating film 40). Is conducting.

A pair of torsion beams 112a and 112b extend inward from a fixed portion 113 formed along a substantially square side. The pair of torsion beams 112 a and 112 b extend from the top surface of the fixing portion 113, and extend at a height separating the gap H from the substrate 42. When the cross section of the pair of torsion beams 112a and 112b is observed from the inside to the outside (when viewed from the bottom to the top in FIGS. 2 and 3), a second insulating film (inner etching resistant film) 90 formed of SiO ₂ is used. Then, a laminated structure of the polycrystalline silicon layer 110 (easy etching film) processed to have conductivity and the third insulating layer (outer etching resistant film) 120 formed of SiO ₂ is observed. The thickness T of the pair of torsion beams 112a and 112b measured in the direction perpendicular to the substrate 10 is thin, and each of the pair of torsion beams 112a and 112b is deformed flexibly. Torsion beams 112a, to constitute a respectively polycrystalline silicon layer 110 of 112b, the conductive via a third movable electrode contact 100 (contact is formed on the second insulating film 90 formed of SiO ₂ window) It is connected to the fixing member 62 having the property.

The swing plate 111 is connected to the inner ends of the pair of torsion beams 112 a and 112 b and extends at a height separated from the substrate 42 by a gap H. When the swing plate 111 is observed from the inside to the outside (when viewed from the bottom to the top in FIGS. 2 and 3), the same laminated structure as the pair of torsion beams 112a and 112b is observed. That is, the second insulating film (inner anti-etching film) 90 are formed of SiO _2, is treated to have conductivity polycrystalline silicon layer 110 (etching-easy film) is formed of SiO ₂ A laminated structure of the third insulating layer (outer etching resistant film) 120 is observed. The polycrystalline silicon layer 110 constituting the swing plate 111 and the polycrystalline silicon layer 110 constituting the pair of torsion beams 112a and 112b are continuous and maintained at the same potential. The polycrystalline silicon layer 110 constituting the oscillating plate 111 faces the first fixed electrode 20a and also faces the second fixed electrode 20b, and forms a movable electrode 115. A reflection surface 161 is formed on the surface of the swing plate 111. The thickness T of the swing plate 111 is equal to the thickness T of the pair of torsion beams 112a and 112b.

The width L of the fixed portion 113 measured in the direction in which the pair of torsion beams 112a and 112b extends, and the gap H between the pair of torsion beams 112a and 112b and the substrate 42 (equal to the gap H between the swing plate 111 and the substrate 42). And a thickness T of the pair of torsion beams 112a and 112b, there is a relationship of L>H> T. Since the width L of the fixing portion 113 is sufficiently thick, even if the height of the fixing portion 113 is increased to increase the gap H, the strength and rigidity to such an extent that the fixing portion 113 is not easily deformed are obtained. Therefore, a large gap H can be obtained. A thickness T of the pair of torsion beams 112a and 112b is sufficiently thin and can be deformed flexibly.
Since the width L of the fixing member 62 is sufficient, even if the height of the fixing portion 113 is increased to increase the gap H, the fixing member 62 does not break. Even if the gap H is increased, there is no disconnection between the movable electrode 115 and the movable electrode wiring 30.
If necessary, the relationship H>L> T can be realized. Since the width L of the fixing member 62 is sufficiently large, even if the height of the fixing portion 113 is made higher than the width L to realize a large gap H, the fixing portion 113 will not be deformed.

  In the micromechanical structure 200, the potential of the movable electrode 115 constituting the swing plate 111 can be adjusted by adjusting the voltage applied to the movable electrode connecting portion 151c. By adjusting the voltage applied to the first fixed electrode connecting portion 150a, the potential of the first fixed electrode 20a fixed to the substrate 10 can be adjusted. By adjusting the voltage applied to the second fixed electrode connecting portion 150b, the potential of the second fixed electrode 20b fixed to the substrate 10 can be adjusted.

  The movable electrode 115 constituting the swing plate 111 and the first fixed electrode 20a fixed to the substrate 10 face each other, and by adjusting the voltage applied to the movable electrode 115 and the first fixed electrode 20a, A suction force can be exerted between the two. That is, it is possible to exert a suction force that attracts the end of the swing plate 111 on the first fixed electrode 20 a side toward the substrate 10. Similarly, the movable electrode 115 constituting the swing plate 111 and the second fixed electrode 20b fixed to the substrate 10 face each other, and the voltage applied to the movable electrode 115 and the second fixed electrode 20b is adjusted. Thus, a suction force can be exerted between the two. That is, it is possible to exert a suction force that attracts the end portion of the swing plate 111 on the second fixed electrode 20 b side toward the substrate 10. The swinging plate 111 can be swung around a straight line connecting the pair of torsion beams 112a and 112b by the above suction force. That is, the directivity direction of the reflecting surface 161 can be swung around a straight line connecting the pair of torsion beams 112a and 112b.

  At this time, the pair of torsion beams 112a and 112b are twisted. As shown in FIG. 2, the pair of torsion beams 112a and 112b have a small thickness T, and as shown in FIG. 1, the pair of torsion beams 112a and 112b have a narrow width W. Each of the pair of torsion beams 112a and 112b is deformed flexibly. That is, excessive stress or excessive strain does not occur in the pair of torsion beams 112a and 112b, and fatigue failure is difficult. Further, the directivity direction of the reflecting surface 161 can be switched by generating a small suction force between the swing plate 111 and the first fixed electrode 20a or between the swing plate 111 and the second fixed electrode 20b. An image forming apparatus with low driving power and high durability can be realized.

(Manufacturing method of the micro mechanical structure of the first embodiment)
4 and subsequent figures show a method for manufacturing the micromechanical structure 200 of the first embodiment. 4 and subsequent figures show cross sections taken along the line EF of FIG. Hereinafter, description will be made with reference to the drawings.

(FIG. 4) Using an ion implantation method (or thermal diffusion) to add and diffuse phosphorus, which is an impurity, at a plurality of locations on the (100) -oriented surface of the substrate 10 made of p-type single crystal silicon. A region (depth of 500 nm) converted into an n-type semiconductor having conductivity because of containing phosphorus in the concentration is formed. The first fixed electrode 20a, the first fixed electrode wiring 21a, the second fixed electrode 20b, the second fixed electrode wiring 21b, and the movable electrode wiring 30 shown in FIGS. 1 to 3 are formed by the conductive n-type semiconductor region. To do.

(FIG. 5) Next, a first insulating film 40 made of a thermal oxide film having etching resistance characteristics is formed to a thickness of 100 nm over the entire surface of the single crystal silicon substrate 10. The single crystal silicon substrate 10 and the first insulating film 40 are collectively referred to as a substrate 42. It can be said that the single crystal silicon substrate 10 is a support plate, the first insulating film 40 is a support plate surface etching resistant layer, and the substrate 42 is formed by both.

(FIG. 6) Next, a second movable electrode contact 50 that penetrates the first insulating film 40 and reaches the movable electrode wiring 30 is formed by photolithography and reactive ion etching. Hereinafter, the flow process of performing photolithography and performing reactive ion etching is referred to as photoetching.

(FIG. 7) Next, a gap forming layer 60 made of polycrystalline silicon having a thickness of 2 μm and having isotropic etching characteristics is formed on the surface of the first insulating film 40 by low pressure CVD. A part of the gap forming layer 60 is used as a sacrificial etching layer 61, and a fixing member 62 is formed by a portion protected from etching.

(FIG. 8) Next, the ion forming method (may be thermal diffusion) is used to add and diffuse phosphorus as an impurity into the gap forming layer 60, and high conductivity is obtained in order to contain phosphorus in a high concentration. Convert to n-type semiconductor. Then, a trench 70 having a width of 800 nm is formed by photoetching at a position serving as an inner boundary of the fixing member 62 manufactured in the subsequent process.

(FIG. 9) A thermal oxide film having a thickness of 1 μm is formed over the entire surface of the gap forming layer 60 in order to embed a thermal oxide film having etching resistance inside the trench 70, and a thermal oxide film 71 is formed inside the trench 70. Fill. The SiO ₂ film 71 filled in the trench 70 defines a region to be a sacrificial etching layer 61 that is etched away in a later process. The SiO ₂ film 71 is hardly etched with respect to the etching agent of the sacrificial etching layer 61 and can be said to be an etching resistant layer. Moreover, it is a layer which is not seen in the torsion beams 112a and 112b and the swing plate 111, and can be said to be an added layer. The thermal oxide film (SiO ₂ film) 71 is an additional etching-resistant film, and is a layer that regulates the range to be the sacrificial etching layer 61 and leaves the fixing member 62.

(FIG. 10) The thermal oxide film 71 produced on the surface of the gap forming layer 60 in FIG. 9 is removed by reactive ion etching or chemical mechanical polishing. The additional thermal oxide film 71 filled in the trench 70 is not removed. In addition, a range outside the range that becomes the fixing member 62 in the gap forming layer 60 is removed by photoetching.

(FIG. 11) A thermal oxide film having a thickness of 200 nm so as to cover the entire exposed surface of the substrate 42, the gap forming layer 60 to be the sacrificial etching layer 61, and the gap forming layer 60 to be the fixing member 62. A second insulating film 90 made of (SiO ₂ film) is formed. The second insulating film 90 is a film that protects the inner surfaces (lower surfaces) of the pair of torsion beams 112a and 112b and the swing plate 111 from etching. The second insulating film 90 can be referred to as an inner etching resistant layer.

(FIG. 12) The third movable electrode contact 100 that penetrates the second insulating film 90 and reaches the fixed member 62 is formed by photoetching.
(FIG. 13) On the surface of the second insulating film 90, a polycrystalline silicon layer 110 to be the movable electrode 115 is formed to a thickness of 200 nm by a low pressure CVD method.
(FIG. 14) The polycrystalline silicon layer 110 to be the movable electrode 115 is diffused by adding phosphorus, which is an impurity, using an ion implantation method (or thermal diffusion) and containing phosphorus in a high concentration. Reform to n-type semiconductor with conductivity. Then, the polycrystalline silicon layer 110 and the second insulating film 90 are etched by photo-etching, and the polycrystalline silicon layer 110 and the second insulating film 90 are changed into the swing plate 111, the first twisted beam 112a, and the second twisted beam. 112b and the shape of the fixed part 113 are patterned. The polycrystalline silicon layer 110 is conductive and will be etched later when the sacrificial etching layer 61 is etched unless protected by an etching resistant layer. The polycrystalline silicon layer 110 can be referred to as an easily etched layer.

(FIG. 15) A third insulating film 120 made of a thermal oxide film (SiO ₂ film) having a thickness of 200 nm is formed over the entire surface of the single crystal silicon substrate 10 including the structure manufactured so far. The third insulating film 120 covers the surface and side surfaces of the polycrystalline silicon layer 110 that becomes the movable electrode 115. Moreover, the surface and side surface of the polycrystalline silicon layer 110 which becomes a part of the pair of torsion beams 112a and 112b are covered. Further, the surface and side surfaces of the polycrystalline silicon layer 110 formed on the top surface of the fixing portion 113 are covered. Furthermore, the side surface of the range used as the fixing member 62 is covered among the gap formation layers 60 which consist of polycrystalline silicon. The third insulating film 120 is a film that protects the outer surfaces (upper surfaces) of the pair of torsion beams 112a and 112b and the swing plate 111 from etching. The third insulating film 90 can be referred to as an outer etching resistant layer. In addition, it can be said to be an etching resistant layer that covers the side surface in the range of the fixing member 62 and protects it from etching.

(FIG. 16) Next, a contact hole penetrating the third insulating film 120, the second insulating film 90, and the first insulating film 40 is formed. At this stage, the first movable electrode contact 130 reaching the movable electrode wiring 30, the first fixed electrode contact 140a (see FIGS. 1 and 3) reaching the first fixed electrode wiring 21a, and the second fixed electrode wiring 21b are reached. Openings are formed in the second fixed electrode contact 140b (see FIGS. 1 and 3) by photoetching.

(FIG. 17) Next, an electrode terminal forming member 150 made of aluminum is formed to a thickness of 800 nm by vacuum deposition or sputtering on the entire surface of the single crystal silicon substrate 10 including the structure manufactured so far. .
(FIG. 18) Next, unnecessary regions of the electrode terminal forming member 150 are removed by photoetching, and the first fixed electrode terminal 150a (see FIGS. 1 and 3) and the second fixed electrode terminal 150b (FIGS. 1 and 3). The movable electrode body terminal 150c is formed.

(FIG. 19) Next, an oxide film serving as the electrode terminal protection film 152 is formed to a thickness of 200 nm over the entire surface of the single crystal silicon substrate 10 including the structure manufactured so far by plasma CVD.
(FIG. 20) Next, unnecessary regions of the electrode terminal protective film 152 are removed by photoetching, and the first fixed electrode terminal protective film 152a (see FIGS. 1 and 3) and the second fixed electrode terminal protective film 152b (see FIG. 20). 1 and FIG. 3), the movable electrode terminal protective film 152c is formed.

(FIG. 21) Next, a reflective surface member 160 made of aluminum is formed to a thickness of 100 nm by vacuum deposition or sputtering over the entire surface of the single crystal silicon substrate 10 including the structure manufactured so far.
(FIG. 22) Next, an unnecessary region of the reflecting surface member 160 is removed by photoetching to form the reflecting surface 161.

(FIG. 23) Next, the first fixed electrode terminal protective film 152a (see FIG. 3), the second fixed electrode terminal protective film 152b (see FIG. 3), and the movable electrode terminal protective film 152c are penetrated. 150a (see FIG. 3), the second fixed electrode terminal 150b (see FIG. 3), and an opening reaching the movable electrode terminal 150c are formed by photoetching, the first fixed electrode connecting portion 151a (see FIG. 3), the second fixed An electrode connecting portion 151b (see FIG. 3) and a movable electrode connecting portion 151c are formed.

(FIG. 24) Next, an etching hole 170 that reaches the sacrificial etching layer 61 through the third insulating film 120 and the second insulating film 90 is formed at a predetermined position in the region to be the sacrificial etching layer 61 (FIG. 24). 1 and FIG. 3). By injecting xenon difluoride (XeF ₂ ) gas into the etching hole 170, all of the sacrificial etching layer 61 formed of polycrystalline silicon is removed by etching, and a gap 80 is formed. The distance H of the gap 80 is equal to the thickness of the sacrificial etching layer 61.
Since XeF ₂ gas does not etch aluminum and the thermal oxide film (etching resistant layer), it is possible to stably manufacture the micromechanical structure 200 having a three-dimensional structure.

The micromechanical structure 200 is formed by selectively and locally etching a laminated plate including the sacrificial etching layer 61. When the fixed portion 113 is observed along the direction in which the movable beams 112a and 112b extend from the side on which the movable beams 112a and 112b extend, a laminated structure of the additional etching resistant layer 71 and the additional easy etching layer 62 is observed. The insulating layers 40, 90 and 120 have an etching resistance and protect the polycrystalline silicon layer 110 which is a conductive easy-etching layer.
The easy etching layer 110 constituting the movable beams 112a and 112b and the additional easy etching layer 62 constituting the fixed portion 113 are the inner etching resistant layers located between the movable beams 112a and 112b and the fixed portion 113. Conduction is made through a hole 50 formed in 90. As shown in FIG. 68, a plurality of unit structures composed of the fixed portion 113, the movable beams 112 a and 112 b and the swing plate 111 are arranged on the common substrate 10.

  In the above manufacturing method, the micromechanical structure is formed from the laminated plate in which the support plate 10, the support plate surface etching resistant layer 40, the gap forming layer 60, the inner etching resistant layer 90, the easy etching layer 110, and the outer etching resistant layer 120 are laminated. The body 200 is manufactured. An additional etching-resistant layer 71 penetrating the gap forming layer 60 is formed at a position where the fixed portion 113 faces the gap 80 existing inside the movable beams 112a and 112b, and an additional forming part of the fixed portion 113 is formed. The gap forming layer 60 to be the easy etching layer 62 includes a step of preparing a laminate in which the support plate surface etching resistant layer 40, the additional etching resistant layer 71, and the outer etching resistant layer 120 are surrounded. Further, the support plate 10 is protected by the support plate surface etching resistant layer 40, and the additional etching resistant layer 71, the inner etching resistant layer 90, and the outer etching resistant layer 120 serve as a fixing member 62 constituting a part of the fixing portion 113. The sacrificial etching layer 61 is etched in a state where the gap forming layer 60 is protected and the easy etching layer 110 is protected by the inner etching resistant layer 90 and the outer etching resistant layer 120, and between the substrate 10 and the movable beams 112a and 112b. A gap H is formed between the substrate 10 and the swing plate 111.

(Second embodiment)
FIGS. 25 to 27 show the structure of the micromechanical structure 200 provided with the oscillating reflection surface 161 of the second embodiment. The members corresponding to those in the first embodiment are denoted by the same reference numerals. The difference from the first embodiment is that a single fixed portion 113 is fixed to the substrate 10 at the center position of the swing plate 111, and the movable beams 112a and 112b extend from the fixed portion 113 to both sides. That is, the swing plate 111 is connected to the tips of the movable beams 112a and 112b.

  When the rocking plate 111 is supported from the center of the rocking plate 111, the thermal stress generated due to the difference in thermal expansion coefficient of different materials when the environmental temperature changes is released. As a result, the heat resistant micro mechanical structure 200 can be realized. The manufacturing method is the same as in the first embodiment.

  In the micro mechanical structure of the second embodiment, a pair of slits 170 and 170 are formed in the vicinity of the center of the swing plate 111, and the movable beams 112 a and 112 b are formed between the pair of slits 170 and 170. The fixing portion 113 is disposed between the pair of slits 170 and 170. The pair of slits 170 and 170 also function as etching holes.

  In FIG. 25, the first fixed electrode 20a may be formed at the right position of the swing plate 111, and the second fixed electrode 20b may be formed at the left position of the swing plate 111. In this case, the swing plate 111 swings as the pair of movable beams 112a and 112b bend. The movable beam that supports the swing plate 111 may be a torsion beam or a bending beam.

(Third example)
FIG. 28 to FIG. 30 show the structure of the micromechanical structure 200 provided with the oscillating reflection surface 161 of the third embodiment. The members corresponding to those in the second embodiment are denoted by the same reference numerals. The difference from the second embodiment is that the grooves 11a and 11b having desired depths are formed by photoetching in a region where the swing plate 111 is in contact with the surface of the substrate 10 in order to further incline the reflecting surface 161. It is. Since the grooves 11a and 11b are formed, the swingable angle of the swing plate 111 is enlarged.

(Fourth embodiment)
FIG. 31 to FIG. 33 show the structure of a micromechanical structure 200 provided with the oscillating reflection surface 161 of the fourth embodiment. The members corresponding to those in the third embodiment are denoted by the same reference numerals. The difference from the third embodiment is that the impact relaxation members 15a and 15b are formed to reduce the impact when the swinging plate 111 contacts the corners of the grooves 11a and 11b. Thereby, the lifetime improvement of the micro mechanical structure 200 is realizable.
34 and 35 show the tilting operation of the swing plate 111 and the deformation state of the impact relaxation member 15a. A desired voltage is applied between the first fixed electrode connecting portion 151a (see FIG. 3) and the movable electrode connecting portion 151c (see FIG. 2). Then, an electrostatic attractive force is generated between the first fixed electrode 20a and the swing plate 111, and the swing plate 111 is attracted toward the first fixed electrode 20a and tilted. Then, the swing plate 111 comes into contact with the first impact relaxation member 15a (FIG. 34), and further, the swing plate 111 tilts while deforming the impact relaxation member 15a (FIG. 35). In this way, the impact mitigating member 15a becomes a cushion and the impact applied to the rocking plate 111 is mitigated, and the life of the micromechanical structure 200 including the rocking reflection surface 161 can be extended.

(Method for producing the micromechanical structure of the fourth embodiment)
36 and the subsequent drawings show a method for manufacturing the micromechanical structure 200 of the fourth embodiment. 36 and subsequent figures are cross sections taken along line PO in FIG. Members corresponding to those of the manufacturing method of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

(FIG. 36) A first groove 11a and a second groove 11b having a depth of 1 μm are formed on the surface of the silicon substrate 10 by photoetching. The first groove 11a is formed at a position where the edge of the swing plate 111 on the side approaching the substrate 10 side is attracted by the first fixed electrode 20a. The second groove 11b is formed at a position where the edge of the swing plate 111 on the side approaching the substrate side is attracted by the second fixed electrode 20b.

(FIG. 37) Impurities are implanted into a plurality of locations on the surface of the substrate 10 and diffused, whereby the first fixed electrode 20a, the first fixed electrode wiring 21a, the second fixed electrode 20b, the second fixed electrode wiring 21b, the movable electrode A wiring 30 is formed.
(FIG. 38) Next, the first insulating film 40 is formed by coating.
(FIG. 39) Next, an opening is formed in the first movable electrode contact 50 by photoetching. In the fourth embodiment, since the fixed portion 113 is provided at the center, the first movable electrode contact 50 is provided at the center.

(FIG. 40) Next, a first gap forming layer 60a having a thickness of 2 μm is formed on the surface of the first insulating film 40.
(FIG. 41) Next, the first gap forming layer 60a is polished by chemical mechanical polishing (hereinafter referred to as CMP). The first gap forming layer 60a is polished until the first insulating film 40 is exposed.

(FIG. 42) Next, a first protective film 12 made of a thermal oxide film having a thickness of 50 nm is formed over the entire surface of the substrate 10, and a polycrystalline silicon layer having a thickness of 100 nm is formed thereon as an impact relaxation film 13. Is formed by a low pressure CVD method.
(FIG. 43) Next, the polycrystalline silicon layer is patterned into the shape of the impact relaxation film 13 by photoetching. Then, a second protective film 14 made of a thermal oxide film having a thickness of 50 nm is formed so as to cover the impact relaxation film 13.
(FIG. 44) Next, unnecessary portions of the second protective film 14 are removed by photoetching to form the first impact relaxation member 15a and the second impact relaxation member 15b.

(FIG. 45) Next, a second gap forming layer 60b having a thickness of 2 μm is formed over the entire surface of the substrate 10.
(FIG. 46) Next, the second gap forming layer 60b is polished by CMP until the surface becomes flat.
(FIG. 47) Next, phosphorus, which is an impurity, is diffused into the first gap formation layer 60a and the second gap formation layer 60b by using an ion implantation method (may be thermal diffusion) to diffuse phosphorus at a high concentration. Therefore, the n-type semiconductor having high conductivity is modified.
Then, a trench 70 that defines a removal range of the sacrificial etching layer 61 to be removed by etching in a later step is formed by using photoetching.

(FIG. 48) Next, a thermal oxide film having a thickness of 1 μm is formed, and the trench 70 is filled with an etching resistant film 71.
(FIG. 49) Next, the thermal oxide film formed on the surface of the second gap forming layer 60b is removed by reactive ion etching or CMP. The thermal oxide film (etching resistant film) 71 filling the trench 70 is not removed.
Then, the second gap forming layer 60b in the range outside the sacrificial etching region 61 is removed by photoetching.

(FIG. 50) Next, the second insulating film 90 is formed over the entire surface of the single crystal silicon substrate 10 on which the above structure is already formed.
(FIG. 51) Next, the second movable electrode contact 100 is formed by photoetching.
(FIG. 52) Next, a polycrystalline silicon layer 110 having a thickness of 200 nm is formed.
(FIG. 53) Next, phosphorus, which is an impurity, is diffused into the polycrystalline silicon layer 110 by ion implantation (may be thermal diffusion) and diffused to increase the conductivity in order to contain phosphorus at a high concentration. The n-type semiconductor is modified. Then, patterning is performed into the shapes of the swing plate 111, the first movable beam 112a (see FIG. 31), the second movable beam 112b (see FIG. 31), and the fixed portion 113 by photoetching.

(FIG. 54) Next, a third insulating film 120 is formed so as to cover the patterned polycrystalline silicon layer 110. The third insulating film 120 covers the surface and side surfaces of the patterned polycrystalline silicon layer 110.

(FIG. 55) Next, the first movable electrode contact 130 (FIGS. 31 and 32), the first fixed electrode contact 140a (FIGS. 31 and 33) reaching the first fixed electrode wiring 21a, and the second fixed electrode wiring A second fixed electrode contact 140b (FIGS. 31 and 33) reaching 21b is formed by photoetching.
(FIG. 56) Next, an electrode terminal forming layer 150 made of aluminum is formed by coating.
(FIG. 57) Next, the first fixed electrode terminal 150a, the second fixed electrode terminal 150b, and the movable electrode terminal 150c (FIG. 32) are formed by photoetching.
(FIG. 58) Next, an electrode terminal protective film 152 is formed.
(FIG. 59) Next, a first fixed electrode terminal protective film 152a, a second fixed electrode terminal protective film 152b, and a movable electrode terminal protective film 152c (FIG. 32) are formed by photoetching.

(FIG. 60) Next, a reflective surface forming layer 160 made of aluminum is formed by coating.
(FIG. 61) Next, an unnecessary region of the reflective surface forming layer 160 is removed by photoetching to form a reflective surface 161.
(FIG. 62) Next, the first fixed electrode connection portion 151a, the second fixed electrode connection portion 151b, and the movable electrode connection portion 151c (FIG. 32) are formed by photoetching.

(FIG. 63) Next, an etching hole 170 is formed at a predetermined position in a region where the sacrificial etching layer 61 spreads.
(FIG. 64) Next, by injecting xenon difluoride (XeF ₂ ) gas into the etching hole 170, all of the sacrificial etching layer 61 is removed by etching to form a gap 80.

(Fifth embodiment)
FIGS. 65 to 67 show the structure of the micromechanical structure 200 provided with the oscillating reflection surface 161 of the fifth embodiment. The members corresponding to those in the fourth embodiment are denoted by the same reference numerals. The difference from the fourth embodiment is that a reinforcing member 114 made of polycrystalline silicon is formed on the swing plate 111. Thereby, since the rigidity of the swing plate 111 is increased, the swing plate 111 is not curved when performing the tilting operation. The reflecting surface 161 swings while maintaining a flat state.

(Sixth embodiment)
68 and 69 show a micromechanical structure including the movable reflecting surface 161 of the sixth embodiment. A plurality of micromechanical structures 200 serving as units shown in any of the first to fifth embodiments are arranged on a common substrate 10. Each oscillating reflection surface 161 performs an inclination operation based on a signal from the drive circuit IC 500 formed in the periphery. A projector or the like can be realized by combining the arrangement of the oscillating reflection surface 161 and the optical system.

(Other examples)
In the above-described embodiment, the first fixed electrode, the first fixed electrode wiring, the second fixed electrode, by adding and diffusing impurities in the polycrystalline silicon at a high concentration using an ion implantation method (may be thermal diffusion), Second fixed electrode wiring and movable electrode wiring are formed. However, the present invention is not limited to this, and polycrystalline silicon processed to have high conductivity characteristics may be used.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The top view of the micro mechanical structure of 1st Example. Sectional drawing of the micro mechanical structure of 1st Example. Sectional drawing orthogonal to FIG. 2 of the micro mechanical structure of 1st Example. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The manufacturing process of the micromechanical structure of 1st Example is shown. The top view of the micro mechanical structure of 2nd Example. Sectional drawing of the micro mechanical structure of 2nd Example. Sectional drawing orthogonal to FIG. 26 of the micro mechanical structure of 2nd Example. The top view of the micro mechanical structure of 3rd Example. Sectional drawing of the micro mechanical structure of 3rd Example. Sectional drawing orthogonal to FIG. 29 of the micro mechanical structure of 3rd Example. The top view of the micro mechanical structure of 4th Example. Sectional drawing of the micro mechanical structure of 4th Example. Sectional drawing orthogonal to FIG. 32 of the micro mechanical structure of 4th Example. The figure explaining operation | movement of the micro mechanical structure of 4th Example. The figure explaining operation | movement of the micro mechanical structure of 4th Example. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The manufacturing process of the micro mechanical structure of 4th Example is shown. The top view of the micro mechanical structure of 5th Example. Sectional drawing of the micro mechanical structure of 5th Example. Sectional drawing orthogonal to FIG. 29 of the micro mechanical structure of 5th Example. The top view of the micro mechanical structure of 6th Example. Sectional drawing of the micro mechanical structure of 6th Example. The figure which shows the manufacturing process of the conventional micro mechanical structure. The figure which shows the manufacturing process of the conventional micro mechanical structure. The figure which shows the manufacturing process of the conventional micro mechanical structure. The figure which shows the manufacturing process of the conventional micro mechanical structure. The figure which shows the manufacturing process of the conventional micro mechanical structure.

Explanation of symbols

10: silicon substrate, support plate 20a: first fixed electrode 20b: second fixed electrode 21a: first fixed electrode wiring 21b: second fixed electrode wiring 30: movable electrode wiring 40: first insulating film, SiO ₂ film, heat Oxide film, support plate surface etching resistant layer 42: substrate 60: gap forming layer 61: sacrificial etching layer 62: fixing member 70: trench 71: additional SiO ₂ film, additional etching resistant layer 80: gap 90: second insulation Film, SiO ₂ film, thermal oxide film, inner etching resistant layer 110: polycrystalline silicon layer, easy etching layer, movable electrode layer 111: swing plates 112a and 112b: torsion beam, movable beam 113: fixed portion 120: third Insulating film, SiO ₂ film, thermal oxide film, outer etching resistant layer 115: movable electrode 161: reflecting surface 170: etching hole, slit 200: micro mechanical structure

Claims (7)

A micromechanical structure formed by locally removing a specific layer constituting the laminate,
A substrate,
A fixed part rising vertically from the substrate;
A movable beam extending in parallel to the substrate at a height that is continuous with the fixed portion and spaced from the substrate;
It has a rocking plate that is connected to the tip of the movable beam and changes the angle between the movable beam and the substrate.
A micromechanical structure characterized in that the width of the fixed part measured in the direction in which the movable beam extends is larger than the thickness of the movable beam measured in the direction perpendicular to the substrate. When the movable beam and the swing plate are observed in a cross section perpendicular to the substrate, an inner etching resistant layer, an easy etching layer, and an outer etching resistant layer are observed in order from the substrate side.
An additional etching-resistant layer and an additional easy-to-etch layer are observed in order from the side of the movable beam when the fixed part is observed in a cross section that is perpendicular to the substrate and extends along the direction in which the movable beam extends. Item 2. The micromechanical structure according to Item 1. The etching resistant layer is formed of an insulating material,
The easy-etching layer is formed of a conductive material,
The easy-etching layer constituting the movable beam and the additional easy-etching layer constituting the fixed part are conducted through a hole formed in the inner etching-resistant layer located between the movable beam and the fixed part. The micromechanical structure according to claim 2, wherein:   4. The micro of claim 1, wherein the height of the fixed portion measured in the direction perpendicular to the substrate is larger than the width of the fixed portion measured in the direction in which the movable beam extends. Mechanical structure.   5. The micromechanical structure according to claim 1, wherein a plurality of unit structures each including a fixed portion, a movable beam, and a swing plate are disposed on a common substrate.   The micromechanical structure according to any one of claims 1 to 5, wherein a reflecting surface is formed on an outer surface of each swing plate. A method for producing a micromechanical structure according to claim 2, wherein the laminate including the gap forming layer is selectively and locally etched.
The support plate, the support plate surface etching resistant layer, the gap forming layer, the inner etching resistant layer, the easy etching layer, and the outer etching resistant layer are laminated, and the gap forming layer is located at the position where the fixed portion faces the inner gap of the movable beam. An additional etch-resistant layer that penetrates the substrate and a gap forming layer that forms an additional easy-etch layer that forms part of the fixed portion is surrounded by the additional etch-resistant layer and the outer etch-resistant layer. And a process of
The support plate surface is protected by an etching resistant layer, and the additional etching resistant layer and the outer etching resistant layer protect the gap forming layer that forms a part of the fixing portion, and the inner etching resistant layer and the outer side. The gap forming layer not protected by the etching resistant layer is etched with the etching resistant layer protected by the etching resistant layer to form a gap between the substrate and the movable beam and between the substrate and the swing plate. A method for manufacturing a micromechanical structure.

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