JP5452197B2 - MEMS optical scanner - Google Patents

MEMS optical scanner Download PDF

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JP5452197B2
JP5452197B2 JP2009275849A JP2009275849A JP5452197B2 JP 5452197 B2 JP5452197 B2 JP 5452197B2 JP 2009275849 A JP2009275849 A JP 2009275849A JP 2009275849 A JP2009275849 A JP 2009275849A JP 5452197 B2 JP5452197 B2 JP 5452197B2
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light
optical scanner
substrate
movable part
mems optical
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JP2011118178A (en
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宏明 橘
清彦 河野
嘉城 早崎
裕志 河田
英喜 上田
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Panasonic Corp
Panasonic Holdings Corp
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Panasonic Corp
Matsushita Electric Industrial Co Ltd
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本発明は、ＭＥＭＳ光スキャナに関するものである。   The present invention relates to a MEMS optical scanner.

近年、マイクロマシニング技術などを利用して形成されるＭＥＭＳ（micro electro mechanical systems）デバイスの一種として、マイクロマシニング技術などを利用して形成されて、光を反射する可動部と、可動部を駆動する駆動手段とを備え、可動部に入射する光を走査するＭＥＭＳ光スキャナが各所で研究開発されている（例えば、特許文献１参照）。なお、この種のＭＥＭＳ光スキャナは、例えば、レーザプロジェクタ、レーザビームプリンタ、バーコードリーダ、内視鏡、距離画像センサなどの種々の光学機器への応用が考えられている。   In recent years, as a type of MEMS (micro electro mechanical systems) device formed using micromachining technology, etc., it is formed using micromachining technology and the like, and a movable portion that reflects light and a movable portion are driven. A MEMS optical scanner that includes a driving unit and scans light incident on a movable part has been researched and developed in various places (for example, see Patent Document 1). Note that this type of MEMS optical scanner is considered to be applied to various optical devices such as a laser projector, a laser beam printer, a barcode reader, an endoscope, and a distance image sensor.

ここにおいて、上記特許文献１には、図１４に示すように、シリコン基板１１０’を用いて形成され一表面側に回折格子５’が設けられた可動部２０’を有する可動部形成基板１’と、可動部形成基板１’の他表面側に接合された支持基板４’とを備えた構成のものが提案されている。ここで、可動部形成基板１’は、矩形枠状の外側フレーム部１０’と、外側フレーム部１０’の内側に配置されミラー面（反射面）２１’に回折格子５’が設けられた矩形板状の可動部２０’と、外側フレーム部１０’の内側で可動部２０’を挟む形で配置され外側フレーム部１０’と可動部２０’とを連結する一対の梁部３１’，３１’とを備えたＭＥＭＳ光スキャナが提案されている。   Here, in Patent Document 1, as shown in FIG. 14, a movable part forming substrate 1 ′ having a movable part 20 ′ formed using a silicon substrate 110 ′ and provided with a diffraction grating 5 ′ on one surface side. And the thing of the structure provided with support substrate 4 'joined to the other surface side of movable part formation board | substrate 1' is proposed. Here, the movable part forming substrate 1 ′ is a rectangular frame-shaped outer frame part 10 ′ and a rectangular shape in which a diffraction grating 5 ′ is provided on a mirror surface (reflection surface) 21 ′ disposed inside the outer frame part 10 ′. A plate-shaped movable portion 20 ′ and a pair of beam portions 31 ′ and 31 ′ that are arranged so as to sandwich the movable portion 20 ′ inside the outer frame portion 10 ′ and connect the outer frame portion 10 ′ and the movable portion 20 ′. A MEMS optical scanner provided with the above has been proposed.

また、上記特許文献１には、図１５に示すように、ＭＥＭＳ光スキャナの回折格子５’により互いに異なる方向に反射された第１の出射光および第２の出射光のうち第１の出射光を画像形成用の画像光（走査光）として利用し、第２の出射光をビームディテクタ６００により検出して可動部２０’の揺動位置を検出することにより、第１の出射光の走査位置を検出するようにした画像形成装置が提案されている。なお、第１の出射光の走査位置は、可動部２０’の機械振れ角により決まるので、第２の出射光をビームディテクタ６００により検出すれば、ビームディテクタ６００の出力に基づいて可動部２０’の機械振れ角を求めることができる。   Further, in Patent Document 1, as shown in FIG. 15, the first outgoing light out of the first outgoing light and the second outgoing light reflected in different directions by the diffraction grating 5 ′ of the MEMS optical scanner. Is used as image light (scanning light) for image formation, the second outgoing light is detected by the beam detector 600, and the swing position of the movable portion 20 ′ is detected, whereby the scanning position of the first outgoing light is detected. There has been proposed an image forming apparatus that detects the above. Since the scanning position of the first emitted light is determined by the mechanical deflection angle of the movable portion 20 ′, if the second emitted light is detected by the beam detector 600, the movable portion 20 ′ is based on the output of the beam detector 600. Can be obtained.

特開２００７−２７２０６６号公報JP 2007-272066 A

しかしながら、図１４に示した構成のＭＥＭＳ光スキャナを用いた画像形成装置では、図１５に示すように、ＭＥＭＳ光スキャナとは別にビームディテクタ６００を配置する必要があるので、生産時に、光源を駆動してＭＥＭＳ光スキャナとビームディテクタ６００との光軸調整（アクティブアライメント）を行う必要があり、生産性が低くなってしまう。また、ＭＥＭＳ光スキャナの回折格子５’とビームディテクタ６００との間の距離が長いので、ビームディテクタ６００の受光面のサイズを大きくする必要があり、ビームディテクタ６００が大型化するとともにコストが高くなってしまう。また、ビームディテクタ６００が大型化すること、回折格子５’とビームディテクタ６００のような受光素子との距離が長くなること、などに起因して、ＭＥＭＳ光スキャナを用いたシステム全体の要求サイズによっては、可動部２０’の機械振れ角を制限して用いる必要が生じることも考えられる。   However, in the image forming apparatus using the MEMS optical scanner having the configuration shown in FIG. 14, it is necessary to dispose the beam detector 600 separately from the MEMS optical scanner as shown in FIG. Therefore, it is necessary to perform optical axis adjustment (active alignment) between the MEMS optical scanner and the beam detector 600, and productivity is lowered. Further, since the distance between the diffraction grating 5 ′ of the MEMS optical scanner and the beam detector 600 is long, it is necessary to increase the size of the light receiving surface of the beam detector 600, which increases the size and cost of the beam detector 600. End up. Further, the size of the beam detector 600 is increased, the distance between the diffraction grating 5 ′ and the light receiving element such as the beam detector 600 is increased, and so on, depending on the required size of the entire system using the MEMS optical scanner. It may be necessary to limit the mechanical deflection angle of the movable part 20 ′.

本発明は上記事由に鑑みて為されたものであり、その目的は、可動部の機械振れ角に応じて出力が変化する受光素子を備えながらも、小型化を図れ且つ可動部の機械振れ角を大きくできるＭＥＭＳ光スキャナを提供することにある。   The present invention has been made in view of the above-described reason, and the object thereof is to provide a light receiving element whose output changes in accordance with the mechanical deflection angle of the movable portion, and to achieve downsizing and the mechanical deflection angle of the movable portion. An object of the present invention is to provide a MEMS optical scanner capable of increasing the size.

請求項１の発明は、半導体基板を用いて形成され、外側フレーム部、外側フレーム部の内側に配置され一表面側にミラー面が設けられた可動部、および外側フレーム部の内側で可動部を挟む形で配置され外側フレーム部と可動部とを連結し捩れ変形が可能な一対の捩りばね部を有する可動部形成基板と、可動部形成基板においてミラー面が設けられた一表面側に接合された第１のカバー基板と、可動部形成基板の他表面側に接合された第２のカバー基板と、可動部を駆動する駆動手段とを備え、可動部形成基板の可動部のミラー面側に回折格子が形成されてなり、第１のカバー基板は、入射光を透過させる入射光透過部、および、０次の回折光である反射光からなる走査光を透過させる走査光透過部が形成されるとともに、０次以外の規定次数の回折光を受光する受光素子が可動部形成基板側に設けられてなることを特徴とする。   The invention of claim 1 is formed using a semiconductor substrate, and includes an outer frame part, a movable part disposed inside the outer frame part and provided with a mirror surface on one surface side, and a movable part inside the outer frame part. A movable part forming substrate having a pair of torsion spring parts that are arranged in a sandwiched manner and can be twisted by connecting the outer frame part and the movable part, and is joined to one surface side of the movable part forming substrate provided with a mirror surface. A first cover substrate, a second cover substrate joined to the other surface side of the movable part forming substrate, and a driving means for driving the movable part, on the mirror surface side of the movable part of the movable part forming substrate. A diffraction grating is formed, and the first cover substrate is formed with an incident light transmitting portion that transmits incident light and a scanning light transmitting portion that transmits scanning light composed of reflected light that is zero-order diffracted light. And other than the zero order Receiving element for receiving the diffracted light, characterized in that is provided on the movable portion substrate side.

この発明によれば、可動部形成基板の可動部のミラー面側に回折格子が形成されてなり、第１のカバー基板は、入射光を透過させる入射光透過部、および、０次の回折光である反射光からなる走査光を透過させる走査光透過部が形成されるとともに、０次以外の規定次数の回折光を受光する受光素子が可動部形成基板側に設けられているので、可動部の機械振れ角に応じて出力が変化する受光素子を備えながらも、小型化を図れ且つ可動部の機械振れ角を大きくできる。また、回折格子の０次の回折光である反射光を走査光として走査光透過部から出射させるので、可動部の機械振れ角を光学振れ角に略一致させることができる。   According to the present invention, the diffraction grating is formed on the mirror surface side of the movable portion of the movable portion forming substrate, the first cover substrate includes the incident light transmitting portion that transmits the incident light, and the 0th-order diffracted light. And a light receiving element for receiving a diffracted light of a specified order other than the 0th order is provided on the movable part forming substrate side. While having a light receiving element whose output changes according to the mechanical deflection angle, it is possible to reduce the size and increase the mechanical deflection angle of the movable part. In addition, since the reflected light, which is the 0th-order diffracted light of the diffraction grating, is emitted as the scanning light from the scanning light transmitting part, the mechanical shake angle of the movable part can be made substantially coincident with the optical shake angle.

請求項２の発明は、請求項１の発明において、前記回折格子は、平面視において格子周期方向に直交する方向を、前記各捩りばね部の並設方向に対して非平行としてあることを特徴とする。   According to a second aspect of the present invention, in the first aspect of the invention, the diffraction grating has a direction orthogonal to the grating periodic direction in plan view that is not parallel to the parallel arrangement direction of the torsion spring portions. And

この発明によれば、前記回折格子は、平面視において格子周期方向に直交する方向を、前記各捩りばね部の並設方向に対して非平行としてあるので、前記入射光と前記走査光を含む平面から前記規定次数の回折光を分離することができ、前記規定次数の回折光を前記走査光とは分離して前記受光素子へ入射させることができる。   According to this invention, the diffraction grating includes the incident light and the scanning light because the direction perpendicular to the grating periodic direction in plan view is not parallel to the parallel arrangement direction of the torsion spring portions. The prescribed order diffracted light can be separated from a plane, and the prescribed order diffracted light can be separated from the scanning light and incident on the light receiving element.

請求項３の発明は、請求項１または請求項２の発明において、前記回折格子は、前記可動部における前記ミラー面側に周期的な溝を設けることにより形成されてなることを特徴とする。   According to a third aspect of the present invention, in the first or second aspect of the present invention, the diffraction grating is formed by providing a periodic groove on the mirror surface side of the movable portion.

この発明によれば、高い回折効率を得ることができる。   According to this invention, high diffraction efficiency can be obtained.

請求項４の発明は、請求項１ないし請求項３の発明において、前記回折格子は、溝形状が鋸歯状であることを特徴とする。   According to a fourth aspect of the present invention, in the first to third aspects of the invention, the diffraction grating has a sawtooth shape in the groove shape.

この発明によれば、前記回折格子の回折効率を高めることができる。   According to this invention, the diffraction efficiency of the diffraction grating can be increased.

請求項５の発明は、請求項１ないし請求項３の発明において、前記回折格子は、溝形状が矩形状であることを特徴とする。   According to a fifth aspect of the present invention, in the first to third aspects of the invention, the diffraction grating has a rectangular groove shape.

この発明によれば、請求項４の発明に比べて、前記回折格子を容易に形成することができる。   According to the present invention, the diffraction grating can be easily formed as compared with the invention of claim 4.

請求項６の発明は、請求項１または請求項２の発明において、前記回折格子は、相対的に反射率の高い材料からなるライン状の高反射率膜と相対的に反射率の低い材料からなるライン状の低反射率膜とが前記ミラー面に沿って交互に配列されてなることを特徴とする。   According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the diffraction grating includes a line-shaped high reflectance film made of a material having a relatively high reflectance and a material having a relatively low reflectance. The line-shaped low reflectance film is alternately arranged along the mirror surface.

この発明によれば、前記回折格子を容易に形成することができる。   According to this invention, the diffraction grating can be easily formed.

請求項７の発明は、請求項６の発明において、前記低反射率膜がＳｉＯ２膜からなり、前記高反射率膜が金属膜であることを特徴とする。 A seventh aspect of the invention is characterized in that, in the sixth aspect of the invention, the low reflectance film is a SiO 2 film, and the high reflectance film is a metal film.

この発明によれば、前記回折格子を一般的なＭＥＭＳプロセスとの整合性の良いプロセスで形成することができる。   According to the present invention, the diffraction grating can be formed by a process having good consistency with a general MEMS process.

請求項８の発明は、請求項１ないし請求項７の発明において、前記規定次数が−１であることを特徴とする。   The invention of claim 8 is characterized in that, in the inventions of claims 1 to 7, the specified order is -1.

この発明によれば、前記受光素子において−１次の回折光を受光するので、−２次以上の回折光を前記受光素子にて受光する場合に比べて、前記受光素子が大きくなりすぎて前記第１のカバー基板の平面サイズが大きくなって小型化が制限されるのを防止することができるとともに、前記受光素子での受光量を増加させることができる。   According to the present invention, since the -1st order diffracted light is received by the light receiving element, the light receiving element becomes too large as compared with the case where the 2nd order or higher order diffracted light is received by the light receiving element. The planar size of the first cover substrate can be prevented from being increased and downsizing can be prevented, and the amount of light received by the light receiving element can be increased.

請求項９の発明は、請求項１ないし請求項８の発明において、前記第１のカバー基板は、前記走査光以外の回折光が外部へ出射するのを遮光する遮光膜が形成されてなることを特徴とする。   According to a ninth aspect of the present invention, in the first to eighth aspects of the invention, the first cover substrate is formed with a light shielding film that shields diffracted light other than the scanning light from being emitted to the outside. It is characterized by.

この発明によれば、前記第１のカバー基板から不要な光が出射されるのを防止することができる。   According to this invention, it is possible to prevent unnecessary light from being emitted from the first cover substrate.

請求項１０の発明は、請求項１ないし請求項９の発明において、前記外側フレーム部と前記第１のカバー基板と前記第２のカバー基板とで囲まれた空間が真空雰囲気であることを特徴とする。   According to a tenth aspect of the present invention, in the first to ninth aspects of the invention, a space surrounded by the outer frame portion, the first cover substrate, and the second cover substrate is a vacuum atmosphere. And

この発明によれば、前記外側フレーム部と前記第１のカバー基板と前記第２のカバー基板とで囲まれた空間が真空雰囲気であることにより、駆動電圧の低電圧化を図りながらも前記可動部の機械振れ角を大きくすることができる。   According to the present invention, the space surrounded by the outer frame portion, the first cover substrate, and the second cover substrate is a vacuum atmosphere, so that the movable voltage can be reduced while reducing the driving voltage. The mechanical deflection angle of the part can be increased.

請求項１の発明では、可動部の機械振れ角に応じて出力が変化する受光素子を備えながらも、小型化を図れ且つ可動部の機械振れ角を大きくできるという効果がある。   According to the first aspect of the present invention, it is possible to reduce the size and increase the mechanical deflection angle of the movable portion while including the light receiving element whose output changes according to the mechanical deflection angle of the movable portion.

実施形態１のＭＥＭＳ光スキャナの概略分解斜視図である。1 is a schematic exploded perspective view of a MEMS optical scanner according to Embodiment 1. FIG. 同上のＭＥＭＳ光スキャナを示し、（ａ）は概略平面図、（ｂ）は（ａ）のＡ−Ａ’概略断面図である。The MEMS optical scanner same as the above is shown, (a) is a schematic plan view, and (b) is an A-A 'schematic cross-sectional view of (a). 同上のＭＥＭＳ光スキャナの動作説明図である。It is operation | movement explanatory drawing of a MEMS optical scanner same as the above. 同上のＭＥＭＳ光スキャナの動作説明図である。It is operation | movement explanatory drawing of a MEMS optical scanner same as the above. 同上のＭＥＭＳ光スキャナの要部概略断面図である。It is a principal part schematic sectional drawing of a MEMS optical scanner same as the above. 同上のＭＥＭＳ光スキャナの製造方法を説明するための主要工程断面図である。It is main process sectional drawing for demonstrating the manufacturing method of a MEMS optical scanner same as the above. 同上のＭＥＭＳ光スキャナの他の構成例の要部概略断面図である。It is a principal part schematic sectional drawing of the other structural example of a MEMS optical scanner same as the above. 同上のＭＥＭＳ光スキャナの別の構成例の要部概略断面図である。It is a principal part schematic sectional drawing of another structural example of a MEMS optical scanner same as the above. 実施形態２のＭＥＭＳ光スキャナの概略分解斜視図である。FIG. 5 is a schematic exploded perspective view of a MEMS optical scanner according to a second embodiment. 実施形態３のＭＥＭＳ光スキャナの概略分解斜視図である。FIG. 6 is a schematic exploded perspective view of a MEMS optical scanner according to a third embodiment. 同上のＭＥＭＳ光スキャナの動作説明図である。It is operation | movement explanatory drawing of a MEMS optical scanner same as the above. 実施形態４のＭＥＭＳ光スキャナの概略分解斜視図である。FIG. 6 is a schematic exploded perspective view of a MEMS optical scanner according to a fourth embodiment. 同上のＭＥＭＳ光スキャナの動作説明図である。It is operation | movement explanatory drawing of a MEMS optical scanner same as the above. 従来例のＭＥＭＳ光スキャナを示し、（ａ）は概略斜視図、（ｂ）は概略分解斜視図である。The MEMS optical scanner of a prior art example is shown, (a) is a schematic perspective view, (b) is a schematic exploded perspective view. 同上のＭＥＭＳ光スキャナを利用した画像形成装置の要部概略説明図である。It is a principal part schematic explanatory drawing of the image forming apparatus using the MEMS optical scanner same as the above.

（実施形態１）
以下、本実施形態のＭＥＭＳ光スキャナについて図１〜図５を参照しながら説明する。 (Embodiment 1)
Hereinafter, the MEMS optical scanner of the present embodiment will be described with reference to FIGS.

本実施形態のＭＥＭＳ光スキャナは、半導体基板であるＳＯＩ基板１００を用いて形成され、外周形状が矩形状の枠状（ここでは、矩形枠状）の外側フレーム部（固定フレーム部）１０、外側フレーム部１０の内側に配置され平面視矩形状のミラー面２１が設けられた平面視矩形状の可動部２０、および外側フレーム部１０の内側で可動部２０を挟む形で配置され外側フレーム部１０と可動部２０とを連結し捩れ変形が可能な一対の捩りばね部３０，３０を有する可動部形成基板（可動部形成基板）１と、第１のガラス基板２００を用いて形成され可動部形成基板１においてミラー面２１が設けられた一表面側に接合された第１のカバー基板２と、第２のガラス基板３００を用いて形成され可動部形成基板１の他表面側に接合された第２のカバー基板３とを備えている。また、本実施形態のＭＥＭＳ光スキャナは、可動部形成基板１の可動部２０のミラー面２１側に回折格子５が形成されている。また、第１のカバー基板２は、光源（例えば、レーザ光源など）からの入射光を透過させる入射光透過部２０３、および、０次の回折光である反射光からなる走査光を透過させる走査光透過部２０４が形成されるとともに、０次以外の規定次数（ここでは、−１）の回折光を受光する受光素子６が可動部形成基板１側に設けられている。   The MEMS optical scanner according to the present embodiment is formed using an SOI substrate 100 which is a semiconductor substrate, and has an outer frame portion (fixed frame portion) 10 having an outer peripheral shape of a rectangular shape (here, a rectangular frame shape) and an outer side. The movable portion 20 having a rectangular shape in plan view and provided with a mirror surface 21 having a rectangular shape in plan view disposed inside the frame portion 10 and the outer frame portion 10 disposed so as to sandwich the movable portion 20 inside the outer frame portion 10. The movable part forming substrate (movable part forming substrate) 1 having a pair of torsion spring parts 30 and 30 that can be torsionally deformed by connecting the movable part 20 and the first glass substrate 200 is formed. The first cover substrate 2 bonded to the one surface side where the mirror surface 21 is provided in the substrate 1 and the second glass substrate 300 is used, and the first cover substrate 2 is bonded to the other surface side of the movable portion forming substrate 1. 2 mosquitoes And a over substrate 3. In the MEMS optical scanner of this embodiment, the diffraction grating 5 is formed on the mirror surface 21 side of the movable part 20 of the movable part forming substrate 1. Further, the first cover substrate 2 scans an incident light transmission unit 203 that transmits incident light from a light source (for example, a laser light source) and scanning light that includes reflected light that is 0th-order diffracted light. A light transmitting portion 204 is formed, and a light receiving element 6 that receives diffracted light of a specified order other than the 0th order (here, −1) is provided on the movable portion forming substrate 1 side.

上述の可動部形成基板１および各カバー基板２，３の外周形状は矩形状であり、各カバー基板２，３は可動部形成基板１と同じ外形寸法に形成されている。   The outer peripheral shape of the above-mentioned movable part forming substrate 1 and each cover substrate 2, 3 is rectangular, and each cover substrate 2, 3 is formed to have the same outer dimensions as the movable part forming substrate 1.

ここにおいて、可動部形成基板１は、導電性を有する第１のシリコン層（活性層）１００ａと第２のシリコン層（シリコン基板）１００ｂとの間に絶縁層（ＳｉＯ２層）１００ｃが介在する上述のＳＯＩ基板１００をバルクマイクロマシニング技術などにより加工することによって形成してある。また、第１のカバー基板２は、それぞれパイレックス（登録商標）ガラスなどからなる２枚のガラス板を厚み方向に重ねて接合した第１のガラス基板２００を用いて形成してあり、第２のカバー基板３は、パイレックス（登録商標）ガラスなどからなる第２のガラス基板３００を加工することにより形成してある。なお、ＳＯＩ基板１００は、第１のシリコン層１００ａの厚さを３０μｍ、第２のシリコン層１００ｂの厚さを４００μｍに設定し、第１のガラス基板２００および第２のガラス基板３００の厚さは、０．５ｍｍ〜１．５ｍｍ程度の範囲で設定してあるが、これらの数値は一例であり、特に限定するものではない。また、半導体基板たるＳＯＩ基板１００の一表面である第１のシリコン層１０ｃの表面は（１００）面としてある。 Here, in the movable part forming substrate 1, an insulating layer (SiO 2 layer) 100c is interposed between a conductive first silicon layer (active layer) 100a and a second silicon layer (silicon substrate) 100b. The SOI substrate 100 described above is formed by processing using a bulk micromachining technique or the like. The first cover substrate 2 is formed using a first glass substrate 200 in which two glass plates each made of Pyrex (registered trademark) glass or the like are stacked in the thickness direction and bonded together. The cover substrate 3 is formed by processing a second glass substrate 300 made of Pyrex (registered trademark) glass or the like. Note that in the SOI substrate 100, the thickness of the first silicon layer 100a is set to 30 μm, the thickness of the second silicon layer 100b is set to 400 μm, and the thicknesses of the first glass substrate 200 and the second glass substrate 300 are set. Is set in the range of about 0.5 mm to 1.5 mm, but these numerical values are examples and are not particularly limited. The surface of the first silicon layer 10c, which is one surface of the SOI substrate 100 as a semiconductor substrate, is a (100) plane.

可動部形成基板１の外側フレーム部１０は、ＳＯＩ基板１００の第１のシリコン層１００ａ、絶縁層１００ｃ、第２のシリコン層１００ｂそれぞれを利用して形成してあり、外側フレーム部１０のうち第１のシリコン層１００ａにより形成された部位が第１のカバー基板２の外周部と全周に亘って接合され、外側フレーム部１０のうち第２のシリコン層１００ｃにより形成された部位が第２のカバー基板３の外周部と全周に亘って接合されており、上記一表面側において外側フレーム部１０に、可動部２０を駆動する後述の駆動手段に電気的に接続される２つのパッド１３，１３が形成されている。各パッド１３，１３は平面視形状が円形状であり、第１の金属膜（例えば、Ａｌ膜など）により構成されている。なお、本実施形態では、各パッド１３，１３の膜厚を５００ｎｍに設定してあるが、この数値は一例であり、特に限定するものではない。   The outer frame portion 10 of the movable portion forming substrate 1 is formed using each of the first silicon layer 100a, the insulating layer 100c, and the second silicon layer 100b of the SOI substrate 100. The portion formed by the first silicon layer 100a is joined to the outer periphery of the first cover substrate 2 over the entire periphery, and the portion formed by the second silicon layer 100c in the outer frame portion 10 is the second. Two pads 13 which are joined to the outer peripheral portion of the cover substrate 3 over the entire periphery and are electrically connected to the outer frame portion 10 on the one surface side, which will be described later, for driving means for driving the movable portion 20; 13 is formed. Each of the pads 13 and 13 has a circular shape in plan view, and is composed of a first metal film (for example, an Al film). In the present embodiment, the thickness of each of the pads 13 and 13 is set to 500 nm, but this numerical value is an example and is not particularly limited.

また、可動部形成基板１の可動部２０および各捩りばね部３０，３０は、ＳＯＩ基板１００の第１のシリコン層１００ａを用いて形成されており、外側フレーム部１０よりも十分に薄肉となっている。また、可動部２０に設けられたミラー面２１は、可動部２０において第１のシリコン層１００ａの表面により構成されているが、これに限らず、可動部２０において第１のシリコン層１００ａにより形成された部位の表面に第２の金属膜（例えば、Ａｌ膜など）からなる反射膜を形成して、当該反射膜の表面が、ミラー面２１を構成するようにしてもよい。なお、反射膜を構成する第２の金属膜の材料は、Ａｌに限らず、走査対象（スキャン対象）の光（入射光）の波長や波長帯に応じて、例えば、Ａｇ、Ａｌ−Ｓｉ、Ａｕなどを採用してもよい。   Further, the movable portion 20 and the torsion spring portions 30, 30 of the movable portion forming substrate 1 are formed using the first silicon layer 100 a of the SOI substrate 100 and are sufficiently thinner than the outer frame portion 10. ing. In addition, the mirror surface 21 provided on the movable portion 20 is configured by the surface of the first silicon layer 100a in the movable portion 20, but is not limited thereto, and is formed by the first silicon layer 100a in the movable portion 20. A reflective film made of a second metal film (for example, an Al film) may be formed on the surface of the formed part, and the surface of the reflective film may constitute the mirror surface 21. Note that the material of the second metal film constituting the reflective film is not limited to Al, and may be, for example, Ag, Al-Si, depending on the wavelength or wavelength band of the light (incident light) of the scan target (scan target). Au or the like may be employed.

以下では、図２（ａ），（ｂ）それぞれの左下に示すように、平面視において一対の捩りばね部３０，３０の並設方向に直交する方向をｘ軸方向、一対の捩りばね部３０，３０の並設方向をｙ軸方向、ｘ軸方向およびｙ軸方向に直交する方向をｚ軸方向とする直交座標を利用して説明する。なお、当該直交座標の原点は、平面視における回折格子５の中心Ｏ（図４参照）としている。   In the following, as shown in the lower left of each of FIGS. 2A and 2B, the direction orthogonal to the juxtaposed direction of the pair of torsion spring portions 30, 30 in plan view is the x-axis direction, and the pair of torsion spring portions 30. , 30 will be described using orthogonal coordinates in which the parallel direction is the y-axis direction, and the direction orthogonal to the x-axis direction and the y-axis direction is the z-axis direction. The origin of the orthogonal coordinates is the center O (see FIG. 4) of the diffraction grating 5 in plan view.

上述の可動部形成基板１は、一対の捩りばね部３０，３０がｙ軸方向に並設されており、可動部２０が、外側フレーム部１０に対して一対の捩りばね部３０，３０の回りで変位可能となっている（ｙ軸の軸回りで回動可能となっている）。つまり、一対の捩りばね部３０，３０は、外側フレーム部１０に対して可動部２０が揺動自在となるように外側フレーム部１０と可動部２０とを連結している。言い換えれば、外側フレーム部１０の内側に配置される可動部２０は、可動部２０から相反する２方向へ連続一体に延長された２つの捩りばね部３０，３０を介して外側フレーム部１０に揺動自在に支持されている。ここで、一対の捩りばね部３０，３０は、両者のｙ軸に沿った中心線同士を結ぶ直線が、平面視で可動部２０の重心を通るように形成されている。なお、各捩りばね部３０，３０は、厚み寸法（ｚ軸に沿った方向の寸法）を３０μｍ、幅寸法（ｘ軸に沿った方向の寸法）を、５μｍに設定してあるが、これらの数値は一例であり、特に限定するものではない。また、可動部２０およびミラー面２１の平面視形状は、矩形状に限らず、例えば、円形状でもよい。また、外側フレーム部１０の内周形状も矩形状に限らず、例えば、円形状でもよい。   In the movable part forming substrate 1 described above, a pair of torsion spring parts 30, 30 are arranged in parallel in the y-axis direction, and the movable part 20 rotates around the pair of torsion spring parts 30, 30 with respect to the outer frame part 10. Can be displaced (can be rotated around the y-axis). That is, the pair of torsion spring portions 30, 30 connects the outer frame portion 10 and the movable portion 20 so that the movable portion 20 can swing with respect to the outer frame portion 10. In other words, the movable part 20 arranged inside the outer frame part 10 swings to the outer frame part 10 via two torsion spring parts 30 and 30 that are continuously and integrally extended in two opposite directions from the movable part 20. It is supported freely. Here, the pair of torsion spring portions 30 and 30 are formed such that a straight line connecting the center lines along the y-axis passes through the center of gravity of the movable portion 20 in plan view. Each of the torsion springs 30 and 30 has a thickness dimension (dimension along the z-axis) set to 30 μm and a width dimension (dimension along the x-axis) set to 5 μm. The numerical value is an example and is not particularly limited. Moreover, the planar view shape of the movable part 20 and the mirror surface 21 is not limited to a rectangular shape, and may be a circular shape, for example. Further, the inner peripheral shape of the outer frame portion 10 is not limited to a rectangular shape, and may be a circular shape, for example.

上述の可動部形成基板１は、可動部２０において一対の捩りばね部３０，３０を結ぶ方向（一対の捩りばね部３０，３０の並設方向）に直交する方向（つまり、ｘ軸方向）の両側に形成された櫛形状の可動電極２２と、外側フレーム部１０に形成され可動電極２２の複数の可動櫛歯片２２ｂに対向する複数の固定櫛歯片１２ｂを有する櫛形状の固定電極１２とで構成され静電力により可動部２０を駆動する静電駆動式の駆動手段を備えている。なお、本実施形態では、駆動手段が、静電力により可動部２０を駆動するものであるが、静電力によって可動部２０を駆動する静電駆動式に限らず、電磁力によって可動部２０を駆動する電磁駆動式でもよいし、圧電素子によって可動部２０を駆動する圧電駆動式でもよい。   In the movable part forming substrate 1 described above, the movable part 20 has a direction (that is, the x-axis direction) orthogonal to a direction connecting the pair of torsion spring parts 30 and 30 (a direction in which the pair of torsion spring parts 30 and 30 are arranged side by side). Comb-shaped movable electrode 22 formed on both sides, and comb-shaped fixed electrode 12 having a plurality of fixed comb-tooth pieces 12b formed on outer frame portion 10 and facing a plurality of movable comb-tooth pieces 22b of movable electrode 22; It is comprised by the electrostatic drive type drive means which drives the movable part 20 by electrostatic force. In the present embodiment, the driving means drives the movable portion 20 by electrostatic force, but is not limited to the electrostatic drive type that drives the movable portion 20 by electrostatic force, and drives the movable portion 20 by electromagnetic force. It may be an electromagnetic driving type, or a piezoelectric driving type in which the movable portion 20 is driven by a piezoelectric element.

上述の固定電極１２，１２は、平面視形状が櫛形状であり、櫛骨部１２ａが外側フレーム部１０のうちｙ軸に沿った枠片部において第１のシリコン層１００ａにより形成された部位の一部により構成されており、櫛骨部１２ａにおける可動部２０との対向面（外側フレーム部１０におけるｙ軸に沿った内側面）には、第１のシリコン層１００ａの一部からなる多数の固定櫛歯片１２ｂが一対の捩りばね部３０，３０の並設方向に沿って列設されている。一方、可動電極２２，２２は、可動部２０における固定電極１２の櫛骨部１２ａ側の櫛骨部２２ａ，２２ａの側面（可動部２０におけるｙ軸に沿った側面）において、第１のシリコン層１００ａの一部により構成され固定櫛歯片１２ｂにそれぞれ対向する多数の可動櫛歯片２２ｂが上記並設方向に列設されている。ここで、櫛形状の固定電極１２と櫛形状の可動電極２２とは、櫛骨部１２ａ，２２ａが互いに対向し、固定電極１２の各固定櫛歯片１２ｂが可動電極２２の櫛溝に入り組んでおり、固定櫛歯片１２ｂと可動櫛歯片２２ｂとが、ｙ軸方向において互いに離間しており、固定電極１２と可動電極２２との間に電圧が印加されることにより、固定電極１２と可動電極２２との間に互いに引き合う方向に作用する静電力が発生する。なお、ｙ軸方向における固定櫛歯片１２ｂと可動櫛歯片２２ｂとの間の隙間は、例えば、５μｍ〜２０μｍ程度の範囲で適宜設定すればよい。   The above-described fixed electrodes 12 and 12 have a comb shape in plan view, and the comb bone portion 12a is a portion of the outer frame portion 10 formed by the first silicon layer 100a in the frame piece portion along the y axis. A part of the comb bone portion 12a facing the movable portion 20 (the inner side surface along the y-axis in the outer frame portion 10) has a large number of parts of the first silicon layer 100a. The fixed comb teeth 12b are arranged along the direction in which the pair of torsion spring portions 30 and 30 are arranged side by side. On the other hand, the movable electrodes 22, 22 are the first silicon layer on the side surfaces (side surfaces along the y axis in the movable portion 20) of the comb bone portions 22 a, 22 a on the comb bone portion 12 a side of the fixed electrode 12 in the movable portion 20. A large number of movable comb teeth 22b that are constituted by a part of 100a and face the fixed comb teeth 12b, respectively, are arranged in the above-mentioned parallel direction. Here, in the comb-shaped fixed electrode 12 and the comb-shaped movable electrode 22, the comb bone portions 12 a and 22 a face each other, and the fixed comb teeth 12 b of the fixed electrode 12 enter the comb groove of the movable electrode 22. The fixed comb tooth piece 12b and the movable comb tooth piece 22b are separated from each other in the y-axis direction, and a voltage is applied between the fixed electrode 12 and the movable electrode 22, whereby the fixed electrode 12 and the movable electrode tooth 22b are movable. An electrostatic force acting in a direction attracting each other is generated between the electrodes 22. In addition, what is necessary is just to set the clearance gap between the fixed comb-tooth piece 12b in the y-axis direction and the movable comb-tooth piece 22b suitably in the range of about 5 micrometers-20 micrometers, for example.

可動部形成基板１の外側フレーム部１０において第１のシリコン層１００ａにより形成された部位には、一方のパッド１３（図１における右側のパッド１３ｂ）が固定電極１２，１２に電気的に接続されるとともに他方のパッド１３（図１における左側のパッド１３ａ）が可動電極２２，２２に電気的に接続され、且つ、固定電極１２，１２と可動電極２２，２２とが電気的に絶縁されるように、複数のスリット１０ａ，１０ａ，１０ａが絶縁層１００ｃに達する深さで形成されている。ここで、本実施形態では、各スリット１０ａ，１０ａ，１０ａをトレンチとし、各スリット１０ａ，１０ａ，１０ａの平面視形状を外側フレーム部１０の外側面側に開放されない形状とすることで、外側フレーム部１０にスリット１０ａ，１０ａ，１０ａを形成した構造を採用しながらも、外側フレーム部１０と第１のカバー基板２との接合性が低下するのを防止し、外側フレーム部１０と各カバー基板２，３とで囲まれる空間の気密性を確保している。   One pad 13 (the right pad 13b in FIG. 1) is electrically connected to the fixed electrodes 12 and 12 at a portion formed by the first silicon layer 100a in the outer frame portion 10 of the movable portion forming substrate 1. And the other pad 13 (left pad 13a in FIG. 1) is electrically connected to the movable electrodes 22 and 22, and the fixed electrodes 12 and 12 and the movable electrodes 22 and 22 are electrically insulated. In addition, a plurality of slits 10a, 10a, 10a are formed to a depth reaching the insulating layer 100c. Here, in this embodiment, each slit 10a, 10a, 10a is made into a trench, and the plan view shape of each slit 10a, 10a, 10a is made into the shape which is not open | released by the outer surface side of the outer side frame part 10, By this While adopting the structure in which the slits 10a, 10a, 10a are formed in the portion 10, it is possible to prevent the bonding property between the outer frame portion 10 and the first cover substrate 2 from being lowered, and the outer frame portion 10 and each cover substrate. The airtightness of the space surrounded by 2 and 3 is secured.

ここで、外側フレーム部１０において第１のシリコン層１００ａにより形成された部分は、上述のスリット１０ａ，１０ａ，１０ａを形成することにより、一端部が可動部２０の外側面に連続一体に連結された各捩りばね部３０，３０それぞれの他端部が内側面に連続一体に連結された２つのアンカー部１１ａ，１１ｂと、一方のアンカー部１１ａａと一方のパッド１３ａが形成された矩形状の島部１１ｃと、上記一方のアンカー部１１ａｂと島部１１ａｃとをつなぐ平面視Ｌ字状の導電部１１ａｄとで構成される第１の導電性構造体１１ａが、可動部２０の可動電極２２，２２と同電位になり、残りの部分からなり他方のパッド１３ｂが形成された第２の導電性構造体１１ｂが固定電極１２，１２と同電位になる。   Here, the portion formed by the first silicon layer 100a in the outer frame portion 10 is connected to the outer surface of the movable portion 20 in an integrated manner by forming the slits 10a, 10a, 10a described above. In addition, the torsion springs 30 and 30 have a rectangular island formed with two anchor portions 11a and 11b in which the other end portions of the torsion spring portions 30 and 30 are continuously and integrally connected to the inner surface, and one anchor portion 11aa and one pad 13a. The first conductive structure 11a composed of the part 11c and the L-shaped conductive part 11ad in plan view connecting the one anchor part 11ab and the island part 11ac is the movable electrodes 22, 22 of the movable part 20. And the second conductive structure 11b formed of the remaining portion and having the other pad 13b formed is at the same potential as the fixed electrodes 12 and 12.

第１のカバー基板２は、上述のように第１のガラス基板２００を用いており、第１のガラス基板２００の厚み方向に貫通して各パッド１３，１３それぞれを全周に亘って露出させる２つの貫通孔２０２，２０２が形成されている。ここにおいて、第１のガラス基板２００の各貫通孔２０２，２０２は、可動部形成基板１から離れるにつれて開口面積が徐々に大きくなるテーパ状に形成されている。ここで、第１のカバー基板２の各貫通孔２０２，２０２は、サンドブラスト法により形成してあるが、サンドブラスト法に限定するものではなく、貫通孔２０２，２０２の形状によってはドリル加工法やエッチング法などを適宜採用してもよい。   As described above, the first cover substrate 2 uses the first glass substrate 200 and penetrates in the thickness direction of the first glass substrate 200 to expose the pads 13 and 13 over the entire circumference. Two through holes 202, 202 are formed. Here, each through-hole 202, 202 of the first glass substrate 200 is formed in a tapered shape in which the opening area gradually increases as the distance from the movable portion forming substrate 1 increases. Here, each of the through holes 202 and 202 of the first cover substrate 2 is formed by the sand blasting method. However, the present invention is not limited to the sand blasting method, and depending on the shape of the through holes 202 and 202, a drilling method or etching is performed. You may employ | adopt a law etc. suitably.

本実施形態のＭＥＭＳ光スキャナでは、各パッド１３，１３の平面視形状を直径が０．５ｍｍの円形状としてあり、各貫通孔２０２，２０２の第１の可動部形成基板１側での開口径が０．５ｍｍよりも大きくなるようにしてあるが、各パッド１３，１３の直径は特に限定するものではなく、また、必ずしも円形状とする必要はなく、例えば、正方形状としてもよいが、貫通孔２０２，２０２の開口径を小さくするうえでは円形状の方が正方形状よりも好ましい。   In the MEMS optical scanner of the present embodiment, the planar view shape of each pad 13, 13 is a circular shape having a diameter of 0.5 mm, and the opening diameter of each through-hole 202, 202 on the first movable part forming substrate 1 side. However, the diameters of the pads 13 and 13 are not particularly limited, and are not necessarily circular, and may be square, for example. In order to reduce the opening diameter of the holes 202, 202, the circular shape is preferable to the square shape.

ここにおいて、各パッド１３，１３の一部が厚み方向において第１のカバー基板２に重なる場合には、パッド１３，１３の厚みの影響で接合性や気密性が損なわれて製造時の歩留まり低下や、動作安定性の低下、経時安定性の低下の原因となる懸念があり、外側フレーム部１０の幅寸法（外側フレーム部１０の外側面と内側面との距離）を増大させる必要が生じてＭＥＭＳ光スキャナの小型化が制限されてしまうことが考えられる。   Here, when a part of each of the pads 13 and 13 overlaps the first cover substrate 2 in the thickness direction, the bondability and the airtightness are impaired due to the thickness of the pads 13 and 13, and the yield during manufacturing is reduced. In addition, there is a concern that the stability of the operation and the stability over time may be deteriorated, and the width dimension of the outer frame portion 10 (the distance between the outer surface and the inner surface of the outer frame portion 10) needs to be increased. It is conceivable that downsizing of the MEMS optical scanner is limited.

これに対して、本実施形態のＭＥＭＳ光スキャナでは、第１のカバー基板２が各パッド１３，１３と重なることがなく、第１のカバー基板２と外側フレーム部１０との間にパッド１３，１３の一部が介在することもないので、第１のカバー基板２と可動部形成基板１の外側フレーム部１０との接合が各パッド１３，１３により妨げられるのを防止することができるから、パッド１３，１３の厚みの影響で接合性や気密性が損なわれるのを防止することができ、外側フレーム部１０の幅寸法を増大させずに歩留まりの向上による低コスト化を図れるとともに、動作安定性の低下、経時安定性の低下を抑制することができる。   On the other hand, in the MEMS optical scanner of the present embodiment, the first cover substrate 2 does not overlap the pads 13 and 13, and the pads 13 and 13 are disposed between the first cover substrate 2 and the outer frame portion 10. Since a part of 13 is not interposed, it is possible to prevent the bonding between the first cover substrate 2 and the outer frame portion 10 of the movable portion forming substrate 1 from being hindered by the pads 13 and 13. It is possible to prevent the bondability and airtightness from being affected by the thickness of the pads 13 and 13 and to reduce the cost by improving the yield without increasing the width dimension of the outer frame portion 10 and to stabilize the operation. It is possible to suppress a decrease in property and a decrease in stability over time.

また、本実施形態のＭＥＭＳ光スキャナでは、可動部形成基板１の外側フレーム部１０と各カバー基板２，３とで囲まれる気密空間を真空とすることで、低消費電力化を図りつつ可動部２０の機械振れ角を大きくすることが可能となるので、上記気密空間を真空とするとともに、第２のカバー基板３における可動部形成基板１との対向面において外側フレーム部１０に接合される部位よりも内側の適宜部位に非蒸発型ゲッタ（図示せず）を設けてある。なお、非蒸発型ゲッタは、例えば、Ｚｒを主成分とする合金やＴｉを主成分とする合金などにより形成すればよい。   In the MEMS optical scanner of the present embodiment, the airtight space surrounded by the outer frame portion 10 of the movable portion forming substrate 1 and each of the cover substrates 2 and 3 is evacuated, so that the movable portion can be achieved while reducing power consumption. Since the mechanical swing angle of 20 can be increased, the airtight space is evacuated, and the second cover substrate 3 is joined to the outer frame portion 10 on the surface facing the movable portion forming substrate 1. A non-evaporable getter (not shown) is provided at an appropriate position inside the housing. The non-evaporable getter may be formed of, for example, an alloy containing Zr as a main component or an alloy containing Ti as a main component.

ところで、第１のガラス基板２００は、可動部形成基板１との対向面に可動部２０の変位空間を確保する変位空間形成用凹部（以下、第１の変位空間形成用凹部と称する）２０１を有しているが、上述のように２枚のガラス板を接合して形成されており、可動部形成基板１に近い側に配置するガラス板（以下、第１のガラス板と称する）において第１の変位空間形成用凹部２０１に対応する部位に厚み方向に貫通する開孔部を形成するとともに可動部形成基板１から遠い側に配置するガラス板（以下、第２のガラス板と称する）を平板状としてあるので、１枚のガラス基板を用いて当該ガラス基板にサンドブラスト加工などにより第１の変位空間形成用凹部２０１を形成する場合に比べて、第１の変位空間形成用凹部２０１の内底面を滑らかな表面とすることができ、第１の変位空間形成用凹部２０１の内底面での拡散反射、光拡散、散乱損失などを低減できる。   By the way, the first glass substrate 200 has a displacement space forming recess (hereinafter referred to as a first displacement space forming recess) 201 that secures a displacement space of the movable portion 20 on the surface facing the movable portion forming substrate 1. In the glass plate (hereinafter referred to as the first glass plate), which is formed by joining two glass plates as described above and arranged on the side close to the movable part forming substrate 1. A glass plate (hereinafter referred to as a second glass plate) which is formed on the side far from the movable part forming substrate 1 while forming an opening portion penetrating in the thickness direction in a portion corresponding to the one displacement space forming recess 201. Since it has a flat plate shape, the inner portion of the first displacement space forming recess 201 is formed in comparison with the case where the first displacement space forming recess 201 is formed on the glass substrate by sandblasting or the like. Smooth bottom It can be a surface, it can be reduced diffuse reflection at the inner bottom surface of the first displacement space forming recess 201, light diffusion, and the like scattering loss.

第２のカバー基板３は、第２のガラス基板３００を用いて形成されており、厚み方向の両面を平面状としてあるが、可動部２０の厚みや、半導体基板を構成するＳＯＩ基板１００の第２のシリコン層１００ｂの厚みなどによっては、第２のガラス基板３００における可動部形成基板１側の一表面に、可動部２０の変位空間を確保するための凹部（以下、第２の変位空間形成用凹部と称する）を形成してもよい。ここにおいて、第２のガラス基板３００の上記一表面に第２の変位空間形成用凹部を形成する場合は、例えば、サンドブラスト法などにより形成すればよい。なお、第２のカバー基板３は、光を透過させる必要がないので、第２のガラス基板３００に限らず、例えば、シリコン基板を用いて形成してもよく、この場合の第２の変位空間形成用凹部は、フォトリソグラフィ技術およびエッチング技術を利用して形成すればよい。   The second cover substrate 3 is formed by using the second glass substrate 300, and both surfaces in the thickness direction are planar, but the thickness of the movable portion 20 and the first of the SOI substrate 100 that constitutes the semiconductor substrate. Depending on the thickness of the second silicon layer 100b and the like, a concave portion (hereinafter referred to as second displacement space formation) for securing a displacement space of the movable portion 20 on one surface of the second glass substrate 300 on the movable portion forming substrate 1 side. May be formed). Here, when the second displacement space forming recess is formed on the one surface of the second glass substrate 300, for example, it may be formed by a sandblast method or the like. Since the second cover substrate 3 does not need to transmit light, the second cover substrate 3 is not limited to the second glass substrate 300 and may be formed using, for example, a silicon substrate. In this case, the second displacement space is used. The formation recess may be formed using a photolithography technique and an etching technique.

なお、上述の各ガラス基板２００，３００のガラス材料としては、ソーダガラス、無アルカリガラス、石英ガラスなどを用いることもできるが、シリコン材料を用いて形成した可動部形成基板１との接合性の観点から、硼珪酸ガラスであるパイレックス（登録商標）やテンパックス（登録商標）などが好ましい。また、本実施形態では、各カバー基板２，３の厚さを０．５ｍｍ〜１．５ｍｍ程度の範囲で設定し、第１の変位空間形成用凹部２０１の深さを０．３ｍｍ程度に設定してあるが、これらの数値は一例であり、特に限定するものではない。   In addition, as a glass material of each of the glass substrates 200 and 300 described above, soda glass, non-alkali glass, quartz glass, and the like can be used, but the bonding property with the movable part forming substrate 1 formed using a silicon material is also possible. From the viewpoint, Pyrex (registered trademark) and Tempax (registered trademark), which are borosilicate glasses, are preferable. In this embodiment, the thickness of each cover substrate 2 and 3 is set in the range of about 0.5 mm to 1.5 mm, and the depth of the first displacement space forming recess 201 is set to about 0.3 mm. However, these numerical values are examples and are not particularly limited.

次に、本実施形態のＭＥＭＳ光スキャナの基本的な動作について簡単に説明する。   Next, the basic operation of the MEMS optical scanner of this embodiment will be briefly described.

本実施形態のＭＥＭＳ光スキャナでは、一対のパッド１３，１３を通して、対向する可動電極２２と固定電極１２との間に可動部２０を駆動するためのパルス電圧を与えることにより、可動電極２２・固定電極１２間に静電力が発生し、可動部２０がｙ軸方向の軸回りで回動する。しかして、本実施形態のＭＥＭＳ光スキャナでは、可動電極２２・固定電極１２間に所定の駆動周波数のパルス電圧を印加することにより、周期的に静電力を発生させることができ、可動部２０を揺動させることができる。   In the MEMS optical scanner of the present embodiment, the movable electrode 22 is fixed by applying a pulse voltage for driving the movable portion 20 between the movable electrode 22 and the fixed electrode 12 facing each other through the pair of pads 13 and 13. An electrostatic force is generated between the electrodes 12, and the movable part 20 rotates about the axis in the y-axis direction. Thus, in the MEMS optical scanner of this embodiment, by applying a pulse voltage having a predetermined drive frequency between the movable electrode 22 and the fixed electrode 12, an electrostatic force can be periodically generated, and the movable unit 20 is It can be swung.

ここで、上述の可動部２０は、内部応力に起因して、静止状態でも水平姿勢（ｘｙ平面に平行な姿勢）ではなく、きわめて僅かであるが傾いているので、例えば、可動電極２２・固定電極１２間にパルス電圧が印加されると、静止状態からであっても、可動部２０に略垂直な方向（ｚ軸方向）の駆動力が加わり、可動部２０が一対の捩りばね部３０，３０を回動軸として当該一対の捩りばね部３０，３０を捩りながら回動する。そして、可動電極２２・固定電極１２間の駆動力を、可動櫛歯片２２ｂと固定櫛歯片１２ｂとが完全に重なりあうような姿勢となったときに解除すると、可動部２０は、慣性力により、一対の捩りばね部３０，３０を捩りながら回動し続ける。そして、可動部２０の回動方向への慣性力と、一対の捩りばね部３０，３０の復元力とが等しくなったとき、当該回動方向への可動部２０の回動が停止する。このとき、可動電極２２・固定電極１２間に再びパルス電圧が印加されて静電力が発生すると、可動部２０は、一対の捩りばね部３０，３０の復元力と可動電極２２および固定電極１２により構成される駆動手段の駆動力により、それまでとは逆の方向への回動を開始する。可動部２０は、駆動手段の駆動力と一対の捩りばね部３０，３０の復元力とによる回動を繰り返して、一対の捩りばね部３０，３０を回動軸として揺動する。   Here, the above-mentioned movable part 20 is not in a horizontal posture (attitude parallel to the xy plane) and is tilted slightly though it is stationary due to internal stress. For example, the movable electrode 22 is fixed. When a pulse voltage is applied between the electrodes 12, a driving force in a direction substantially perpendicular to the movable portion 20 (z-axis direction) is applied even from a stationary state, so that the movable portion 20 has a pair of torsion spring portions 30, The pair of torsion springs 30 and 30 are rotated while twisting about 30 as a rotation axis. Then, when the driving force between the movable electrode 22 and the fixed electrode 12 is released when the movable comb tooth piece 22b and the fixed comb tooth piece 12b are in a posture that completely overlaps, the movable portion 20 has an inertial force. Thus, the pair of torsion springs 30 and 30 continue to rotate while twisting. Then, when the inertial force in the rotational direction of the movable portion 20 and the restoring force of the pair of torsion spring portions 30 and 30 become equal, the rotation of the movable portion 20 in the rotational direction stops. At this time, when an electrostatic force is generated again by applying a pulse voltage between the movable electrode 22 and the fixed electrode 12, the movable portion 20 is caused by the restoring force of the pair of torsion spring portions 30, 30 and the movable electrode 22 and the fixed electrode 12. By the driving force of the configured driving means, the rotation in the opposite direction is started. The movable portion 20 repeats the rotation by the driving force of the driving means and the restoring force of the pair of torsion spring portions 30 and 30, and swings about the pair of torsion spring portions 30 and 30 as the rotation shaft.

本実施形態のＭＥＭＳ光スキャナでは、可動部２０と一対の捩りばね部３０，３０とにより構成される振動系の共振周波数の略２倍の周波数のパルス電圧を印加することにより、可動部２０が共振現象を伴って駆動され、機械振れ角（ｘｙ平面に平行な水平面を基準としたときの傾き）が大きくなる。なお、可動電極２２・固定電極１２間への電圧（駆動電圧）の印加形態や周波数は特に限定するものではなく、例えば、可動電極２２・固定電極１２間に印加する電圧を正弦波電圧としてもよい。   In the MEMS optical scanner of this embodiment, the movable part 20 is applied by applying a pulse voltage having a frequency approximately twice the resonance frequency of the vibration system constituted by the movable part 20 and the pair of torsion spring parts 30 and 30. Driven with a resonance phenomenon, the mechanical deflection angle (tilt with respect to a horizontal plane parallel to the xy plane) increases. The application form and frequency of the voltage (drive voltage) between the movable electrode 22 and the fixed electrode 12 are not particularly limited. For example, the voltage applied between the movable electrode 22 and the fixed electrode 12 may be a sine wave voltage. Good.

ところで、本実施形態のＭＥＭＳ光スキャナは、上述のように、可動部形成基板１の可動部２０のミラー面２１上に回折格子５が形成されている。なお、本実施形態の回折格子５は、ミラー面２１上に金属膜（例えば、Ａｌ膜など）を成膜した後、フォトリソグラフィ技術およびエッチング技術を利用して当該金属膜を等間隔で平行配置される複数のライン状の金属膜５ａ（図５参照）にパターニングすることで形成されている。言い換えれば、回折格子５は、可動部２０における第１のカバー基板２側に周期的な溝５ｂ（図５参照）を設けることにより形成されており、高い回折効率を得ることができる。また、本実施形態では、回折格子５の溝５ｂの形状（溝形状）を矩形状（断面矩形状）としてあるので、回折格子５を容易に形成することができる。なお、本実施形態では、回折格子５の格子周期をｄ（図５参照）とすると、走査対象（スキャン対象）の光の波長や入射角に基づいて、格子周期ｄを例えば２μｍ〜２０μｍ程度の範囲で適宜設定すればよい。   By the way, in the MEMS optical scanner of this embodiment, the diffraction grating 5 is formed on the mirror surface 21 of the movable part 20 of the movable part forming substrate 1 as described above. In the diffraction grating 5 of the present embodiment, after a metal film (for example, an Al film) is formed on the mirror surface 21, the metal film is arranged in parallel at equal intervals using a photolithography technique and an etching technique. It is formed by patterning a plurality of line-shaped metal films 5a (see FIG. 5). In other words, the diffraction grating 5 is formed by providing the periodic groove 5b (see FIG. 5) on the first cover substrate 2 side in the movable portion 20, and high diffraction efficiency can be obtained. In the present embodiment, since the shape (groove shape) of the groove 5b of the diffraction grating 5 is rectangular (cross-sectional rectangular shape), the diffraction grating 5 can be easily formed. In this embodiment, when the grating period of the diffraction grating 5 is d (see FIG. 5), the grating period d is, for example, about 2 μm to 20 μm based on the wavelength or incident angle of light of the scanning target (scanning target). What is necessary is just to set suitably in the range.

ところで、図３に示すように、回折格子５に入射光が入射すると、回折格子５からは各次数（回折の次数）の回折光が出射される。図３には、０次の回折光（反射光）、１次の回折光、２次の回折光、−１次の回折光、−２次の回折光、−３次の回折光のみ図示してあるが、本実施形態では、０次の回折光である反射光を走査光として第１のカバー基板２から出射させるようにし、−１次の回折光を第１のカバー基板２の受光素子６に入射させるようにしてある。具体的には、第１のカバー基板２には、入射光を透過させる入射光透過部２０３と、０次の回折光である反射光からなる走査光を透過させる走査光透過部２０４と−１次の回折光を入射させる受光素子６とが各別に設けられている。ここで、第１のカバー基板２は、第１のガラス基板２００における可動部形成基板１側とは反対側の表面のうち、入射光透過部２０３および走査光透過部２０４それぞれに対応する部位以外の領域の適宜範囲に、金属膜などからなる遮光膜（図示せず）を、蒸着法やスパッタ法やめっき法などを利用して形成してある。言い換えれば、第１のカバー基板２は、走査光以外の回折光が外部へ出射するのを遮光する上記遮光膜が形成されているので、第１のカバー基板２から不要な光が出射されるのを防止することができる。なお、上記遮光膜の材料としては、光の吸収率の高い材料を採用する方が光の多重反射に起因した迷光を低減する点で好ましく、金属以外の材料により形成してもよい。また、本実施形態では、上記遮光膜が、外部からの光が受光素子６へ入射するのを防止する機能も有しているので、受光素子６の出力が外部からの光に起因して変化するのを防止することができる。   As shown in FIG. 3, when incident light enters the diffraction grating 5, the diffraction grating 5 emits diffracted light of each order (diffraction order). FIG. 3 shows only 0th-order diffracted light (reflected light), 1st-order diffracted light, 2nd-order diffracted light, −1st-order diffracted light, −2nd-order diffracted light, and −3rd-order diffracted light. However, in the present embodiment, the reflected light, which is the 0th-order diffracted light, is emitted from the first cover substrate 2 as the scanning light, and the −1st-order diffracted light is received by the light receiving element of the first cover substrate 2. 6 is made incident. Specifically, the first cover substrate 2 includes an incident light transmitting portion 203 that transmits incident light, and a scanning light transmitting portion 204 that transmits scanning light composed of reflected light that is 0th-order diffracted light, and −1. A light receiving element 6 for allowing the next diffracted light to enter is provided separately. Here, the first cover substrate 2 is a portion other than the portion corresponding to each of the incident light transmitting portion 203 and the scanning light transmitting portion 204 on the surface of the first glass substrate 200 opposite to the movable portion forming substrate 1 side. A light-shielding film (not shown) made of a metal film or the like is formed in an appropriate range of the region using a vapor deposition method, a sputtering method, a plating method, or the like. In other words, since the first cover substrate 2 is formed with the light shielding film that shields the diffracted light other than the scanning light from being emitted to the outside, unnecessary light is emitted from the first cover substrate 2. Can be prevented. As the material for the light-shielding film, it is preferable to use a material having a high light absorptivity from the viewpoint of reducing stray light due to multiple reflection of light, and it may be formed of a material other than metal. In the present embodiment, the light shielding film also has a function of preventing light from the outside from entering the light receiving element 6, so that the output of the light receiving element 6 changes due to the light from the outside. Can be prevented.

本実施形態では、入射透過部２０３および走査光透過部２０４を、第１のガラス基板２００の一部により構成しているが、入射透過部２０３および走査光透過部２０４は、それぞれ第１のガラス基板２００の厚み方向に貫通する透孔を形成してから当該透孔に走査対象の光に対して透明な材料を充填して形成してもよい。なお、第１のカバー基板２は、第１のガラス基板２００に限らず、例えば、アクリル基板や金属板を用いて形成してもよく、アクリル基板を用いて形成する場合には、第１のガラス基板２００を用いて形成する場合と同様に上記遮光膜を設けることで入射透過部２０３および走査光透過部２０４を形成してもよいし、入射透過部２０３および走査光透過部２０４それぞれに対応する部位に透孔を形成してから当該透孔に走査対象の光に対して透明な材料を充填して形成してもよく、また、金属板を用いて形成する場合には、入射透過部２０３および走査光透過部２０４それぞれに対応する部位に透孔を形成してから当該透孔に走査対象の光に対して透明な材料を充填して形成してもよい。   In the present embodiment, the incident transmission part 203 and the scanning light transmission part 204 are configured by a part of the first glass substrate 200. However, the incident transmission part 203 and the scanning light transmission part 204 are each a first glass. A through hole penetrating in the thickness direction of the substrate 200 may be formed, and then the through hole may be filled with a material that is transparent to the light to be scanned. The first cover substrate 2 is not limited to the first glass substrate 200, and may be formed using, for example, an acrylic substrate or a metal plate. As in the case of forming using the glass substrate 200, the light-shielding film may be provided to form the incident transmissive part 203 and the scanning light transmissive part 204, or corresponding to the incident transmissive part 203 and the scanning light transmissive part 204, respectively. The through hole may be formed in a portion to be filled and then filled with a material transparent to the light to be scanned. In addition, in the case of using a metal plate, the incident transmission portion Alternatively, a through hole may be formed in a portion corresponding to each of 203 and the scanning light transmitting portion 204, and then the through hole may be filled with a material transparent to the light to be scanned.

ところで、０次の回折光である反射光は、入射光と等しい角度で出射されるのに対して、０次以外の回折光は、入射光よりも大きい角度あるいは小さい角度で出射されることとなる。本実施形態では、反射光（主光線）を走査光として第１のカバー基板２の走査光透過部２０３から出射させ、負の次数の回折光のうち規定次数（ここでは、−１）の回折光（副光線）を振れ角検出光として受光素子６へ入射させる。   By the way, reflected light which is 0th-order diffracted light is emitted at an angle equal to incident light, whereas diffracted light other than 0th-order is emitted at an angle larger or smaller than incident light. Become. In the present embodiment, reflected light (principal ray) is emitted as scanning light from the scanning light transmitting portion 203 of the first cover substrate 2, and diffraction of a specified order (here, -1) out of negative order diffracted light. Light (secondary light beam) is incident on the light receiving element 6 as deflection angle detection light.

ここで、回折格子５の溝５ｂの延長方向（格子周期方向に直交する方向）が一対の捩りばね部３０，３０の並設方向に平行な場合、一対の捩りばね部３０，３０の並設方向に直交する平面（ｘｚ平面）に沿って回折格子５に入射光を入射させると、全ての回折光が同一平面（ｘｚ平面）上に存在することとなり、ＭＥＭＳ光スキャナの走査光として必要な光のみを出射させることが困難となる。つまり、可動部２０が一対の捩りばね部３０，３０を回動軸として回動したときに、主光線が描く走査線からなる主走査線と、副光線が描く副走査線とが重なってしまう。   Here, when the extending direction of the groove 5b of the diffraction grating 5 (the direction orthogonal to the grating periodic direction) is parallel to the parallel arrangement direction of the pair of torsion spring portions 30, 30, the parallel arrangement of the pair of torsion spring portions 30, 30 is performed. When incident light is incident on the diffraction grating 5 along a plane orthogonal to the direction (xz plane), all the diffracted light exists on the same plane (xz plane), which is necessary as scanning light for the MEMS optical scanner. It becomes difficult to emit only light. That is, when the movable unit 20 rotates about the pair of torsion springs 30 and 30 as the rotation axis, the main scanning line composed of the scanning line drawn by the principal ray overlaps the sub-scanning line drawn by the sub-ray. .

これに対して、本実施形態のＭＥＭＳ光スキャナでは、図４に示すように、可動部２０の機械振れ角が０°の状態で当該回折格子５の中心に立てた法線がｚ軸上にある一方で、一対の捩りばね部３０，３０がｙ軸上にあり、回折格子５の溝５ｂ（図５参照）の延長方向（回折格子５の格子周期方向に直交する方向）を、ｘｙ平面においてｙ軸に対して反時計周り方向に所定角φだけ傾けてある。なお、所定角φはｘｙ平面においてｙ軸に対して反時計周り方向を正としてあるが、所定角φは負でもよい（つまり、溝５ｂの延長方向はｘｙ平面においてｙ軸に対して時計回り方向に傾けてもよい）。   In contrast, in the MEMS optical scanner of this embodiment, as shown in FIG. 4, the normal line set up at the center of the diffraction grating 5 with the mechanical deflection angle of the movable part 20 being 0 ° is on the z-axis. On the other hand, the pair of torsion springs 30 and 30 are on the y-axis, and the extending direction of the groove 5b (see FIG. 5) of the diffraction grating 5 (the direction orthogonal to the grating periodic direction of the diffraction grating 5) is defined on the xy plane. In FIG. 1, the angle is tilted by a predetermined angle φ counterclockwise with respect to the y-axis. The predetermined angle φ is positive in the counterclockwise direction with respect to the y axis in the xy plane, but the predetermined angle φ may be negative (that is, the extension direction of the groove 5b is clockwise with respect to the y axis in the xy plane). Can be tilted in the direction).

要するに、本実施形態における回折格子５は、平面視において格子周期方向に直交する方向を、一対の捩りばね部３０，３０の並設方向に対して非平行としてある。また、本実施形態では、一対の捩りばね部３０，３０の並設方向に直交する方向に、入射光透過部２０３と走査光透過部２０４とを並設するとともに、細長の長方形状の走査光透過部２０４の長手方向を一致させてあり、平面視において、一対の捩りばね部３０，３０の並設方向に沿って走査光透過部２０４と受光素子６とが並ぶように受光素子６を配置してある。しかして、一対の捩りばね部３０，３０の並設方向に直交する平面に沿って回折格子５に入射光を入射させて用いる場合に、回折格子５からの０次の回折光である反射光を当該平面に沿って進行させて第１のカバー基板２の走査光透過部２０４から出射させる一方で、上記規定次数（−１）の回折光を当該平面から傾いた面に沿って進行させ受光素子６に入射させることができる。なお、所定角φは、上記規定次数の回折光と他の回折光とを分離でき主走査線と副走査線とが分離されるように適宜設定すればよい。   In short, the diffraction grating 5 in the present embodiment has a direction orthogonal to the grating periodic direction in plan view that is not parallel to the parallel arrangement direction of the pair of torsion spring portions 30 and 30. In the present embodiment, the incident light transmitting portion 203 and the scanning light transmitting portion 204 are arranged in parallel in a direction orthogonal to the parallel arrangement direction of the pair of torsion spring portions 30 and 30, and the elongated rectangular scanning light is provided. The light-receiving elements 6 are arranged so that the scanning light transmission parts 204 and the light-receiving elements 6 are aligned along the direction in which the pair of torsion springs 30 and 30 are arranged in a plan view. It is. Thus, when incident light is incident on the diffraction grating 5 along a plane orthogonal to the direction in which the pair of torsion spring portions 30 and 30 are arranged side by side, the reflected light is zero-order diffracted light from the diffraction grating 5. Is allowed to travel along the plane to be emitted from the scanning light transmitting portion 204 of the first cover substrate 2, while the diffracted light of the specified order (−1) travels along a plane inclined from the plane to receive light. The light can enter the element 6. The predetermined angle φ may be set as appropriate so that the diffracted light of the specified order and other diffracted light can be separated and the main scanning line and the sub-scanning line are separated.

第１のカバー基板２の受光素子６は、上記規定次数の回折光（副光線）を受光できる位置に配置されている。受光素子６としては、フォトダイオードや、ＰＳＤのような半導体位置検出素子（光位置センサ）などが、レーザ光源のような光源からの光による回折光に対する波長選択性や応答性の観点で好ましい。ここで、受光素子６としてフォトダイオードを採用する場合には、可動部２０が一対の捩りばね部３０，３０を回動軸として回動したときに副光線が描く走査線からなる副走査線を全て受光できるようにアレイ化し、副光線の到達位置の全てで検出するようにしてもよいし、副走査線上の数箇所の位置で検出して可動部２０の機械振れ角を内挿あるいは外挿して求めるようにしてもよい。これに対して、受光素子６として、ＰＳＤを用いると受光素子６上に形成される副走査線の全長に亘って副光線の到達位置を連続的に検出することができるので、受光素子６の出力に基づいて可動部２０の機械振れ角を求める際の精度を高めることが可能となる。なお、第１のカバー基板２には、受光素子６の出力用の貫通孔配線（図示せず）が形成されており、上記遮光膜とは絶縁膜（図示せず）などにより適宜絶縁されている。   The light receiving element 6 of the first cover substrate 2 is disposed at a position where it can receive the diffracted light (secondary light beam) of the specified order. As the light receiving element 6, a photodiode or a semiconductor position detecting element (optical position sensor) such as PSD is preferable from the viewpoint of wavelength selectivity and responsiveness to diffracted light by light from a light source such as a laser light source. Here, when a photodiode is employed as the light receiving element 6, a sub-scanning line composed of a scanning line drawn by a sub-beam when the movable unit 20 rotates about the pair of torsion springs 30 and 30 as rotation axes is used. It may be arranged in an array so that all light can be received and detected at all of the arrival positions of the sub-rays, or it is detected at several positions on the sub-scanning line and the mechanical deflection angle of the movable part 20 is interpolated or extrapolated. You may make it ask. On the other hand, if PSD is used as the light receiving element 6, the arrival position of the sub-rays can be continuously detected over the entire length of the sub scanning line formed on the light receiving element 6. It is possible to improve the accuracy when obtaining the mechanical deflection angle of the movable part 20 based on the output. The first cover substrate 2 is provided with through-hole wiring (not shown) for output of the light receiving element 6 and is appropriately insulated from the light shielding film by an insulating film (not shown) or the like. Yes.

以下、本実施形態のＭＥＭＳ光スキャナの製造方法について図６を参照しながら説明するが、（ａ）〜（ｄ）は図２（ａ）のＡ−Ｂ’断面に対応する部分の概略断面を示している。   Hereinafter, the manufacturing method of the MEMS optical scanner according to the present embodiment will be described with reference to FIG. 6, and (a) to (d) are schematic cross sections of portions corresponding to the cross section AB ′ of FIG. Show.

まず、半導体基板であるＳＯＩ基板１００の上記一表面側に所定膜厚（例えば、５００ｎｍ）の金属膜（例えば、Ａｌ膜など）をスパッタ法や蒸着法などにより成膜する金属膜形成工程を行い、フォトリソグラフィ技術およびエッチング技術を利用して金属膜をパターニングすることにより各パッド１３，１３および回折格子５を形成する金属膜パターニング工程を行うことによって、図６（ａ）に示す構造を得る。なお、本実施形態では、各パッド１３，１３と回折格子５のライン状の金属膜５ａ（図５参照）との材料および膜厚を同じに設定してあるので、各パッド１３，１３と回折格子５とを同時に形成しているが、各パッド１３，１３と回折格子５の金属膜５ａとの材料や膜厚が相違する場合には、各パッド１３，１３を形成するパッド形成工程と回折格子５を形成する回折格子形成工程とを別々に設ければよく、パッド形成工程と回折格子形成工程との順序はどちらが先でもよい。   First, a metal film forming step is performed in which a metal film (for example, an Al film) having a predetermined film thickness (for example, 500 nm) is formed on the one surface side of the SOI substrate 100, which is a semiconductor substrate, by sputtering or vapor deposition. Then, by performing a metal film patterning process for forming the pads 13 and 13 and the diffraction grating 5 by patterning the metal film using a photolithography technique and an etching technique, the structure shown in FIG. 6A is obtained. In the present embodiment, the materials and film thicknesses of the pads 13 and 13 and the line-shaped metal film 5a (see FIG. 5) of the diffraction grating 5 are set to be the same. Although the grating 5 is formed at the same time, if the materials and film thicknesses of the pads 13 and 13 and the metal film 5a of the diffraction grating 5 are different, the pad forming process for forming the pads 13 and 13 and diffraction are performed. The diffraction grating forming process for forming the grating 5 may be provided separately, and the order of the pad forming process and the diffraction grating forming process may be either.

上述の各パッド１３，１３および回折格子５を形成した後、ＳＯＩ基板１００の上記一表面側で、第１のシリコン層１００ａのうち可動部２０、一対の捩りばね部３０，３０、外側フレーム部１０、固定電極１２，１２、可動電極２２，２２に対応する部位を覆うようにパターニングされた第１のレジスト層１３０をマスクとして、第１のシリコン層１００ａを絶縁層１００ｃに達する深さ（第１の所定深さ）までエッチングすることにより第１のシリコン層１００ａをパターニングする第１のシリコン層パターニング工程（表面側パターニング工程）を行うことによって、図６（ｂ）に示す構造を得る。要するに、第１のシリコン層パターニング工程は、半導体基板であるＳＯＩ基板１００を上記一表面から第１の所定深さまでエッチングする表面側パターニング工程を構成している。第１のシリコン層パターニング工程での第１のシリコン層１００ａのエッチングは、誘導結合プラズマ（ＩＣＰ）型のエッチング装置などの異方性の高いエッチングが可能なドライエッチング装置により行えばよい。また、第１のシリコン層パターニング工程では、絶縁層１００ｃをエッチングストッパ層として利用している。   After forming the pads 13 and 13 and the diffraction grating 5, the movable portion 20, the pair of torsion spring portions 30 and 30, and the outer frame portion of the first silicon layer 100a are formed on the one surface side of the SOI substrate 100. 10. Depth reaching the first silicon layer 100a to the insulating layer 100c using the first resist layer 130 patterned so as to cover the portions corresponding to the fixed electrodes 12 and 12 and the movable electrodes 22 and 22 (a first thickness). The structure shown in FIG. 6B is obtained by performing a first silicon layer patterning step (surface side patterning step) for patterning the first silicon layer 100a by etching to a predetermined depth of 1). In short, the first silicon layer patterning step constitutes a surface side patterning step of etching the SOI substrate 100, which is a semiconductor substrate, from the one surface to a first predetermined depth. Etching of the first silicon layer 100a in the first silicon layer patterning step may be performed by a dry etching apparatus capable of highly anisotropic etching such as an inductively coupled plasma (ICP) type etching apparatus. In the first silicon layer patterning step, the insulating layer 100c is used as an etching stopper layer.

上述の第１のシリコン層パターニング工程の後、ＳＯＩ基板１００の上記一表面側の第１のレジスト層１３０を除去してから、ＳＯＩ基板１００の上記一表面側の全面に第２のレジスト層１３１を形成し、続いて、ＳＯＩ基板１００の他表面側で、第２のシリコン層１００ｂのうち外側フレーム部１０に対応する部位以外を露出させるようにパターニングされた第３のレジスト層１３２をマスクとして、第２のシリコン層１００ｂを絶縁層１００ｃに達する深さ（第２の所定深さ）までエッチングすることにより第２のシリコン層１００ｂをパターニングする第２のシリコン層パターニング工程を行うことによって、図６（ｃ）に示す構造を得る。要するに、第２のシリコン層パターニング工程は、半導体基板であるＳＯＩ基板１００を上記他表面から第２の所定深さまでエッチングする裏面側パターニング工程を構成している。第２のシリコン層パターニング工程での第２のシリコン層１００ｂのエッチングは、誘導結合プラズマ（ＩＣＰ）型のエッチング装置などの異方性が高く垂直深堀が可能なドライエッチング装置により行えばよい。また、第２のシリコン層パターニング工程では、絶縁層１００ｃをエッチングストッパ層として利用している。   After the first silicon layer patterning step, the first resist layer 130 on the one surface side of the SOI substrate 100 is removed, and then the second resist layer 131 is formed on the entire surface on the one surface side of the SOI substrate 100. Then, on the other surface side of the SOI substrate 100, the third resist layer 132 patterned so as to expose the second silicon layer 100b other than the portion corresponding to the outer frame portion 10 is used as a mask. By performing a second silicon layer patterning step of patterning the second silicon layer 100b by etching the second silicon layer 100b to a depth (second predetermined depth) reaching the insulating layer 100c, FIG. The structure shown in 6 (c) is obtained. In short, the second silicon layer patterning step constitutes a back side patterning step of etching the SOI substrate 100, which is a semiconductor substrate, from the other surface to a second predetermined depth. Etching of the second silicon layer 100b in the second silicon layer patterning step may be performed by a dry etching apparatus that has high anisotropy and enables vertical deepening, such as an inductively coupled plasma (ICP) etching apparatus. In the second silicon layer patterning step, the insulating layer 100c is used as an etching stopper layer.

上述の第２のシリコン層パターニング工程の後、ＳＯＩ基板１００の絶縁層１００ｃにおいて外側フレーム部１０と可動部２０との間の部位、可動電極２２，２２と固定電極１２，１２との間の部位を、ＳＯＩ基板１００の上記他表面側からエッチングする絶縁層パターニング工程を行うことで可動部形成基板１を形成してから、第２のレジスト層１３１および第３のレジスト層１３２を除去し、その後、可動部形成基板１と、第１のカバー基板２および第２のカバー基板３とを陽極接合などにより接合する接合工程を行うことによって、図６（ｄ）に示す構造のＭＥＭＳ光スキャナを得る。   After the above-described second silicon layer patterning step, a portion between the outer frame portion 10 and the movable portion 20 and a portion between the movable electrodes 22, 22 and the fixed electrodes 12, 12 in the insulating layer 100c of the SOI substrate 100. After forming the movable part forming substrate 1 by performing an insulating layer patterning step of etching from the other surface side of the SOI substrate 100, the second resist layer 131 and the third resist layer 132 are removed, and then Then, the MEMS optical scanner having the structure shown in FIG. 6D is obtained by performing a bonding step of bonding the movable part forming substrate 1 to the first cover substrate 2 and the second cover substrate 3 by anodic bonding or the like. .

ここにおいて、接合工程では、可動部形成基板１のミラー面２１を保護する観点から、第１のカバー基板２と可動部形成基板１とを接合する第１の接合過程を行ってから、可動部形成基板１と第２のカバー基板３とを接合する第２の接合過程を行うことが好ましい。ここで、第１の接合過程では、先ず、第１のガラス基板２００に第１の変位空間形成用凹部２０１や各貫通孔２０２，２０２を形成した第１のカバー基板２と可動部形成基板１とを重ねた積層体を、所定真空度（例えば、１０Ｐａ以下）の真空中で所定の接合温度（例えば、３００℃〜４００℃程度）に加熱した状態で、第１のシリコン層１００ａと第１のカバー基板２との間に第１のカバー基板２側を低電位側として所定電圧（例えば、４００Ｖ〜８００Ｖ程度）を印加し、この状態を所定の接合時間（例えば、２０分〜６０分程度）だけ保持すればよい。また、第２の接合過程では、上述の第１の接合過程に準じて、第２のシリコン層１００ｂと第２のカバー基板３との陽極接合を行う。なお、可動部形成基板１と各カバー基板２，３を接合する接合方法は、陽極接合に限らず、例えば、常温接合法などでもよい。また、第１のシリコン層パターニング工程の後に、ＳＯＩ基板１００と第１のカバー基板２とを接合し、その後、第２のシリコン層パターニング工程、絶縁層パターニング工程を行うことで可動部形成基板１を形成し、その後、可動部形成基板１と第２のカバー基板３とを接合するようにしてもよい。   Here, in the joining step, from the viewpoint of protecting the mirror surface 21 of the movable part forming substrate 1, a first joining process for joining the first cover substrate 2 and the movable part forming substrate 1 is performed, and then the movable part. It is preferable to perform a second bonding process for bonding the formation substrate 1 and the second cover substrate 3 together. Here, in the first bonding process, first, the first cover substrate 2 and the movable portion forming substrate 1 in which the first displacement space forming recesses 201 and the through holes 202 and 202 are formed in the first glass substrate 200. And the first silicon layer 100a and the first layer are heated in a vacuum at a predetermined degree of vacuum (for example, 10 Pa or less) to a predetermined bonding temperature (for example, about 300 ° C. to 400 ° C.). A predetermined voltage (for example, about 400V to 800V) is applied between the first cover substrate 2 and the cover substrate 2 with the first cover substrate 2 side as a low potential side, and this state is maintained for a predetermined bonding time (for example, about 20 minutes to 60 minutes). Only hold). In the second bonding process, anodic bonding between the second silicon layer 100b and the second cover substrate 3 is performed in accordance with the first bonding process described above. In addition, the joining method for joining the movable part forming substrate 1 and the cover substrates 2 and 3 is not limited to anodic joining, and for example, a room temperature joining method may be used. In addition, after the first silicon layer patterning step, the SOI substrate 100 and the first cover substrate 2 are bonded together, and then the second silicon layer patterning step and the insulating layer patterning step are performed, whereby the movable part forming substrate 1. After that, the movable part forming substrate 1 and the second cover substrate 3 may be bonded to each other.

ところで、本実施形態のＭＥＭＳ光スキャナの製造方法では、接合工程が終了するまでの全工程を可動部形成基板１および各カバー基板２，３それぞれについてウェハレベルで行うことでＭＥＭＳ光スキャナを複数備えたウェハレベルパッケージ構造体を形成するようにし、当該ウェハレベルパッケージ構造体から個々のＭＥＭＳ光スキャナに分割する分割工程を行うようにしている。要するに、本実施形態のＭＥＭＳ光スキャナの製造方法では、可動部形成基板１を複数形成した第１のウェハと、第１のカバー基板２を複数形成した第２のウェハおよび第２のカバー基板３を複数形成した第３のウェハとを接合することでウェハレベルパッケージ構造体を形成した後、ウェハレベルパッケージ構造体から可動部形成基板１の外形サイズに分割するようにしているので、各カバー基板２，３の平面サイズを可動部形成基板１の外形サイズに合わせることができるから、受光素子６を備え、小型で且つ機械振れ角が大きなＭＥＭＳ光スキャナを簡易なプロセスで製造することができ、また、量産性を高めることができる。   By the way, in the manufacturing method of the MEMS optical scanner according to the present embodiment, a plurality of MEMS optical scanners are provided by performing all the processes until the bonding process is completed on the movable part forming substrate 1 and each of the cover substrates 2 and 3 at the wafer level. A wafer level package structure is formed, and a dividing step of dividing the wafer level package structure into individual MEMS optical scanners is performed. In short, in the manufacturing method of the MEMS optical scanner of the present embodiment, the first wafer on which a plurality of movable part forming substrates 1 are formed, the second wafer on which a plurality of first cover substrates 2 are formed, and the second cover substrate 3. After the wafer level package structure is formed by joining the third wafer formed with a plurality of wafers, the wafer level package structure is divided into the outer size of the movable part forming substrate 1. Since the plane size of 2 or 3 can be adjusted to the external size of the movable part forming substrate 1, a small-sized MEMS optical scanner having a large mechanical deflection angle can be manufactured by a simple process. Moreover, mass productivity can be improved.

以上説明した本実施形態のＭＥＭＳ光スキャナでは、可動部形成基板１の可動部２０のミラー面２１側に回折格子５が形成されてなり、第１のカバー基板２は、入射光を透過させる入射光透過部２０３、および、０次の回折光である反射光からなる走査光を透過させる走査光透過部２０４が形成されるとともに、０次以外の規定次数の回折光を受光する受光素子６が可動部形成基板１側に設けられているので、可動部２０の機械振れ角に応じて出力が変化する受光素子６を備えながらも、小型化を図れ且つ可動部２０の機械振れ角を大きくできる。また、回折格子５の０次の回折光である反射光を走査光として走査光透過部２０３から出射させるので、可動部２０の機械振れ角を光学振れ角に略一致させることができる。   In the MEMS optical scanner of the present embodiment described above, the diffraction grating 5 is formed on the mirror surface 21 side of the movable part 20 of the movable part forming substrate 1, and the first cover substrate 2 is incident to transmit incident light. A light transmitting portion 203 and a scanning light transmitting portion 204 that transmits scanning light composed of reflected light that is 0th-order diffracted light are formed, and a light receiving element 6 that receives diffracted light of a specified order other than the 0th order is formed. Since it is provided on the movable portion forming substrate 1 side, it is possible to reduce the size and increase the mechanical deflection angle of the movable portion 20 while including the light receiving element 6 whose output changes according to the mechanical deflection angle of the movable portion 20. . In addition, since the reflected light, which is the 0th-order diffracted light of the diffraction grating 5, is emitted as scanning light from the scanning light transmitting portion 203, the mechanical shake angle of the movable portion 20 can be made substantially coincident with the optical shake angle.

ところで、図１４に示した従来構成のＭＥＭＳ光スキャナでは、可動部形成基板１’の上記一表面側が開放されており、可動部２０’と一対の梁部３１’，３１’とで構成される振動系が空気雰囲気にあるので、空気抵抗の影響で機械振れ角が小さくなってしまい、また、回折格子５’の酸化により回折格子５’の回折特性が経時変化してしまう懸念がある。   By the way, in the conventional MEMS optical scanner shown in FIG. 14, the one surface side of the movable part forming substrate 1 ′ is opened, and is constituted by the movable part 20 ′ and a pair of beam parts 31 ′ and 31 ′. Since the vibration system is in an air atmosphere, the mechanical deflection angle becomes small due to the effect of air resistance, and there is a concern that the diffraction characteristics of the diffraction grating 5 ′ may change over time due to oxidation of the diffraction grating 5 ′.

これに対して、本実施形態のＭＥＭＳ光スキャナでは、可動部形成基板１の外側フレーム部１０と第１のカバー基板２と第２のカバー基板３とで囲まれた空間が真空雰囲気であることにより、駆動電圧の低電圧化を図りながらも可動部２０の機械振れ角を大きくすることができる。ただし、外側フレーム部１０と第１のカバー基板２と第２のカバー基板３とで囲まれた空間を不活性ガス雰囲気（例えば、ドライ窒素ガス雰囲気など）としてもよく、真空雰囲気とした場合、不活性ガス雰囲気とした場合のいずれも、回折格子５の酸化を防止できるから、回折格子５の材料の選択肢が多くなるとともに、回折格子５の回折特性の経時変化を抑制することができる。   On the other hand, in the MEMS optical scanner of the present embodiment, the space surrounded by the outer frame portion 10, the first cover substrate 2, and the second cover substrate 3 of the movable portion forming substrate 1 is a vacuum atmosphere. As a result, it is possible to increase the mechanical deflection angle of the movable portion 20 while reducing the drive voltage. However, the space surrounded by the outer frame portion 10, the first cover substrate 2 and the second cover substrate 3 may be an inert gas atmosphere (for example, a dry nitrogen gas atmosphere). In any case where the inert gas atmosphere is used, oxidation of the diffraction grating 5 can be prevented, so that the choice of the material of the diffraction grating 5 is increased, and a change in the diffraction characteristics of the diffraction grating 5 with time can be suppressed.

また、本実施形態のＭＥＭＳ光スキャナでは、回折格子５は、平面視において格子周期方向に直交する方向を、各捩りばね部３０，３０の並設方向に対して非平行としてあるので、入射光と走査光を含む平面から規定次数の回折光を分離することができるので、規定次数の回折光を走査光とは分離して受光素子６に入射させることができる。   Further, in the MEMS optical scanner of the present embodiment, the diffraction grating 5 has a direction orthogonal to the grating periodic direction in a plan view that is not parallel to the parallel arrangement direction of the torsion spring portions 30 and 30. Since the diffracted light of the specified order can be separated from the plane including the scanning light, the diffracted light of the specified order can be separated from the scanning light and incident on the light receiving element 6.

また、本実施形態では、上記規定次数を−１としてあるので、受光素子６において−１次の回折光を受光するから、−２次以上の回折光を受光素子６にて受光する場合に比べて、受光素子６が大きくなりすぎて第１のカバー基板２の平面サイズが大きくなって小型化が制限されるのを防止することができるとともに、受光素子６での受光量を増加させることができる。   Further, in the present embodiment, since the specified order is −1, the light receiving element 6 receives −1st order diffracted light, so that the −2nd order or higher order diffracted light is received by the light receiving element 6. Therefore, it is possible to prevent the light receiving element 6 from becoming too large and the planar size of the first cover substrate 2 to be increased, thereby restricting downsizing, and to increase the amount of light received by the light receiving element 6. it can.

また、本実施形態のＭＥＭＳ光スキャナでは、回折格子５は、可動部２０のミラー面２１側に周期的な溝５ｂを設けることにより形成されているので、高い回折効率を得ることができる。   Further, in the MEMS optical scanner of the present embodiment, the diffraction grating 5 is formed by providing the periodic groove 5b on the mirror surface 21 side of the movable portion 20, so that high diffraction efficiency can be obtained.

また、本実施形態のＭＥＭＳ光スキャナでは、ＳＯＩ基板１００の第１のシリコン層１００ａにより各捩りばね部３０，３０を形成してあるので、半導体基板としてシリコン基板を用いる場合に比べて各捩りばね部３０，３０の厚み寸法の精度を高めることができ、可動部２０と一対の捩りばね部３０，３０とで構成される振動系の共振周波数の精度を高めることができる。   In the MEMS optical scanner of this embodiment, the torsion springs 30 and 30 are formed by the first silicon layer 100a of the SOI substrate 100. Therefore, each torsion spring is compared with a case where a silicon substrate is used as the semiconductor substrate. The precision of the thickness dimension of the parts 30 and 30 can be raised, and the precision of the resonant frequency of the vibration system comprised by the movable part 20 and a pair of torsion spring parts 30 and 30 can be raised.

ところで、回折格子５の溝５ｂの形状である溝形状を矩形状としてあるが、図７に示すように、溝５ｂの形状である溝形状を鋸歯状とすれば、回折格子５の回折効率をより高めることができる。ここで、溝５ｂの周期（格子周期）ｄおよび鋸歯面の角度γは、走査対象の光の波長や入射角に基づいて適宜設定すればよい。ただし、図５に示したように、溝５ｂの溝形状を矩形状とした方が、鋸歯状の場合に比べて、回折格子５を容易に形成することができる。ここで、溝形状が鋸歯状の溝５ｂを形成するには、例えば、インプリント法を利用して鋸歯状の溝形状に対応する断面形状のエッチングマスク層を形成してから、エッチングを行うようにしたり、フォトリソグラフィ工程とエッチング工程とを繰り返し行うことで所定レベル（階調数）の階段構造を形成するようにしてもよい（例えば、１６レベルの階段構造を有する回折格子５を形成するようにしてもよい）。なお、回折格子５の溝５ｂの形状は特に矩形状や鋸歯状に限らず、周期的に溝５ｂが形成されていればよい。また、回折格子５は、可動部２０に直接形成してもよい（第１のシリコン層１００ａに溝５ｂを形成することで形成してもよい）。   By the way, although the groove shape which is the shape of the groove 5b of the diffraction grating 5 is a rectangular shape, as shown in FIG. 7, if the groove shape which is the shape of the groove 5b is a sawtooth shape, the diffraction efficiency of the diffraction grating 5 is increased. Can be increased. Here, the period (grating period) d of the groove 5b and the angle γ of the sawtooth surface may be set as appropriate based on the wavelength and incident angle of the light to be scanned. However, as shown in FIG. 5, the diffraction grating 5 can be formed more easily when the groove shape of the groove 5b is rectangular than when the groove shape is sawtooth. Here, in order to form the groove 5b having a serrated groove shape, for example, an etching mask layer having a cross-sectional shape corresponding to the sawtooth groove shape is formed by using an imprint method, and then etching is performed. Or a step structure having a predetermined level (the number of gradations) may be formed by repeatedly performing a photolithography process and an etching process (for example, the diffraction grating 5 having a 16-level step structure may be formed). It may be) In addition, the shape of the groove 5b of the diffraction grating 5 is not limited to a rectangular shape or a sawtooth shape, and the groove 5b may be formed periodically. The diffraction grating 5 may be formed directly on the movable portion 20 (may be formed by forming the groove 5b in the first silicon layer 100a).

また、回折格子５は、図８に示すように、相対的に反射率の高い材料からなるライン状（直線状）の高反射率膜たる金属膜５ａと相対的に反射率の低い材料からなるライン状（直線状）の低反射率膜たるＳｉＯ２膜５ｃとがミラー面２１に沿って交互に配列された構成としてもよく、この場合も、回折格子５を容易に形成することができる。ここで、低反射率膜がＳｉＯ２膜５ｃからなり、高反射率膜が金属膜５ａであることにより、回折格子５を一般的なＭＥＭＳプロセスとの整合性の良いプロセスで形成することができる。なお、高反射率膜として用いる金属膜としては、Ａｌ−Ｓｉ膜、Ａｌ膜、Ａｕ膜などを採用すれば、反射率が高く且つ膜質のよい薄膜を得ることができるが、低反射率膜と高反射率膜との材料の組み合わせは、走査対象の光の波長に応じて適宜決定すればよい。 Further, as shown in FIG. 8, the diffraction grating 5 is made of a material having a relatively low reflectivity and a metal film 5a that is a linear (linear) high reflectivity film made of a material having a relatively high reflectivity. The SiO 2 films 5c, which are linear (linear) low reflectivity films, may be arranged alternately along the mirror surface 21, and in this case, the diffraction grating 5 can be easily formed. Here, since the low reflectance film is made of the SiO 2 film 5c and the high reflectance film is the metal film 5a, the diffraction grating 5 can be formed by a process having good consistency with a general MEMS process. . As the metal film used as the high reflectivity film, if an Al-Si film, an Al film, an Au film, or the like is employed, a thin film having high reflectivity and good film quality can be obtained. What is necessary is just to determine the combination of a material with a high reflectance film | membrane suitably according to the wavelength of the light of scanning object.

（実施形態２）
本実施形態のＭＥＭＳ光スキャナの基本構成は実施形態１と略同じであって、図９に示すように、第１のカバー基板２において、入射光透過部２０３、走査光透過部２０４、受光素子６の配置が相違する。なお、実施形態１と同様の構成要素には同一の符号を付して説明を省略する。 (Embodiment 2)
The basic configuration of the MEMS optical scanner of the present embodiment is substantially the same as that of the first embodiment, and as shown in FIG. 9, in the first cover substrate 2, an incident light transmitting portion 203, a scanning light transmitting portion 204, a light receiving element. The arrangement of 6 is different. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

本実施形態では、一対の捩りばね部３０，３０の並設方向に沿って入射光透過部２０３と走査光透過部２０４とを並設してあり、可動部２０の回転軸を含む平面（ｙｚ平面）に沿って入射光を入射させれば、０次の回折光である反射光（主光線）を走査光として走査光透過部２０４から出射させることができ、規定次数（ここでは、−１）の回折光（副光線）を受光素子６に入射させることができる。本実施形態では、細長の走査光透過部２０４の長手方向を一対の捩りばね部３０，３０の並設方向に直交する方向に合わせることができるので、より大きな機械振れ角に対応することができる。   In the present embodiment, the incident light transmitting portion 203 and the scanning light transmitting portion 204 are provided in parallel along the direction in which the pair of torsion spring portions 30 and 30 are provided in parallel, and a plane (yz) including the rotation axis of the movable portion 20. If incident light is incident along a plane, reflected light (principal light), which is zero-order diffracted light, can be emitted as scanning light from the scanning light transmission unit 204, and the specified order (here, −1) ) Diffracted light (sub-beam) can be made incident on the light receiving element 6. In the present embodiment, the longitudinal direction of the elongated scanning light transmitting portion 204 can be matched with the direction orthogonal to the direction in which the pair of torsion spring portions 30 and 30 are arranged side by side, so that a larger mechanical deflection angle can be accommodated. .

（実施形態３）
本実施形態のＭＥＭＳ光スキャナの基本構成は実施形態２と略同じであって、図１０に示すように、回折格子５の格子周期方向を、一対の捩りばね部３０，３０の並設方向に一致させてある点（つまり、図４のφを９０°としてある点）が相違するだけである。なお、実施形態２と同様の構成要素には同一の符号を付して説明を省略する。 (Embodiment 3)
The basic configuration of the MEMS optical scanner according to the present embodiment is substantially the same as that of the second embodiment, and as shown in FIG. The only difference is that they match (that is, the point where φ in FIG. 4 is 90 °). In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 2, and description is abbreviate | omitted.

本実施形態では、図１１に示すように、回折格子５の縞方向が一対の捩りばね部３０，３０の並設方向に直交しており、反射光である主光線が描く主走査線と、規定次数（図示例では、−１）の回折光である副光線が描く副走査線とをずらすことができ、φ＝９０°としたことで、主走査線と副走査線とを最も離すことができる。さらに、本実施形態のＭＥＭＳ光スキャナでは、可動部２０の回転軸を含む平面（ｙｚ平面）に沿って入射光を入射させるようにすれば、主走査線の中心および副走査線の中心が、入射光および回転軸と同一平面（ｙｚ平面）上に揃うので、受光素子６の中心を副走査線の中心に一致させることにより、実施形態１で説明した上記駆動手段を制御する制御装置のマイクロコンピュータなどの演算部による受光素子６の出力の取り扱いが容易になる（演算部において受光素子６の出力に基づいて可動部２０の機械振れ角を求める演算が容易になる）。   In the present embodiment, as shown in FIG. 11, the stripe direction of the diffraction grating 5 is orthogonal to the juxtaposed direction of the pair of torsion spring portions 30, 30, and the main scanning line drawn by the principal ray as reflected light; The sub-scanning line drawn by the sub-ray which is the diffracted light of the specified order (-1 in the illustrated example) can be shifted, and by setting φ = 90 °, the main scanning line and the sub-scanning line are separated most. Can do. Furthermore, in the MEMS optical scanner of the present embodiment, if incident light is incident along a plane (yz plane) including the rotation axis of the movable portion 20, the center of the main scanning line and the center of the sub scanning line are Since the incident light and the rotation axis are aligned on the same plane (yz plane), the center of the light receiving element 6 is made to coincide with the center of the sub-scanning line, thereby controlling the driving device described in the first embodiment. It becomes easy to handle the output of the light receiving element 6 by a calculation unit such as a computer (calculation for obtaining the mechanical deflection angle of the movable unit 20 based on the output of the light receiving element 6 in the calculation unit).

（実施形態４）
本実施形態のＭＥＭＳ光スキャナの基本構成は実施形態１と略同じであって、図１２に示すように、回折格子５の格子周期方向を、一対の捩りばね部３０，３０の並設方向に一致させてある点（つまり、図４のφを９０°としてある点）が相違するだけである。なお、実施形態１と同様の構成要素には同一の符号を付して説明を省略する。 (Embodiment 4)
The basic configuration of the MEMS optical scanner of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 12, the grating period direction of the diffraction grating 5 is set in the direction in which the pair of torsion spring portions 30 and 30 are arranged side by side. The only difference is that they match (that is, the point where φ in FIG. 4 is 90 °). In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

本実施形態では、図１３に示すように、回折格子５の縞方向が一対の捩りばね部３０，３０の並設方向に直交しており、反射光である主光線が描く主走査線と、規定次数（図示例では、−１）の回折光である副光線が描く副走査線とを一対の捩りばね部３０，３０の並設方向に平行な方向にずらすことができ、φ＝９０°としたことで、主走査線と副走査線とを最も離すことができる。さらに、本実施形態のＭＥＭＳ光スキャナでは、可動部２０の回転軸を含む平面（ｙｚ平面）に沿って入射光を入射させるようにすれば、主走査線の中心および副走査線の中心が、入射光および回転軸と同一平面（ｘｙ平面）上に揃うので、受光素子６の中心を副走査線の中心に一致させることにより、実施形態１で説明した上記駆動手段を制御する制御装置のマイクロコンピュータなどの演算部による受光素子６の出力の取り扱いが容易になる（演算部において受光素子６の出力に基づいて可動部２０の機械振れ角を求める演算が容易になる）。   In the present embodiment, as shown in FIG. 13, the stripe direction of the diffraction grating 5 is orthogonal to the juxtaposed direction of the pair of torsion spring portions 30, 30, and the main scanning line drawn by the chief ray as reflected light; A sub-scanning line drawn by a sub-beam that is diffracted light of a specified order (-1 in the illustrated example) can be shifted in a direction parallel to the parallel direction of the pair of torsion spring portions 30 and 30, φ = 90 ° Thus, the main scanning line and the sub-scanning line can be separated most. Furthermore, in the MEMS optical scanner of the present embodiment, if incident light is incident along a plane (yz plane) including the rotation axis of the movable portion 20, the center of the main scanning line and the center of the sub scanning line are Since the incident light and the rotation axis are aligned on the same plane (xy plane), the center of the light receiving element 6 is made to coincide with the center of the sub-scanning line, thereby controlling the driving device described in the first embodiment. It becomes easy to handle the output of the light receiving element 6 by a calculation unit such as a computer (calculation for obtaining the mechanical deflection angle of the movable unit 20 based on the output of the light receiving element 6 in the calculation unit).

ところで、上記各本実施形態のＭＥＭＳ光スキャナにおいて、各パッド１３それぞれの代わりに、例えば、第１のカバー基板２の外表面と可動部形成基板１における外側フレーム部１０の表面と貫通孔２０２の内側面とに跨って形成された貫通配線を外部接続電極として形成してもよい。   By the way, in the MEMS optical scanner of each of the above-described embodiments, instead of each pad 13, for example, the outer surface of the first cover substrate 2, the surface of the outer frame portion 10 in the movable portion forming substrate 1, and the through holes 202. A through wiring formed across the inner side surface may be formed as an external connection electrode.

１ 可動部形成基板
２ 第１のカバー基板
３ 第２のカバー基板
５ 回折格子
５ａ 金属膜（高反射率膜）
５ｂ 溝
５ｃ ＳｉＯ２膜（低反射率膜）
６ 受光素子
１０ 外側フレーム部
１２ 固定電極
２０ 可動部
２１ ミラー面
２２ 可動電極
３０ 捩りばね部
１００ ＳＯＩ基板（半導体基板）
２０３ 入射光透過部
２０４ 走査光透過部 DESCRIPTION OF SYMBOLS 1 Movable part formation board 2 1st cover board 3 2nd cover board 5 Diffraction grating 5a Metal film (high reflectivity film)
5b groove 5c SiO 2 film (low reflectance film)
6 Light Receiving Element 10 Outer Frame 12 Fixed Electrode 20 Movable Part 21 Mirror Surface 22 Movable Electrode 30 Torsion Spring Part 100 SOI Substrate (Semiconductor Substrate)
203 Incident light transmission part 204 Scanning light transmission part

Claims (10)

半導体基板を用いて形成され、外側フレーム部、外側フレーム部の内側に配置され一表面側にミラー面が設けられた可動部、および外側フレーム部の内側で可動部を挟む形で配置され外側フレーム部と可動部とを連結し捩れ変形が可能な一対の捩りばね部を有する可動部形成基板と、可動部形成基板においてミラー面が設けられた一表面側に接合された第１のカバー基板と、可動部形成基板の他表面側に接合された第２のカバー基板と、可動部を駆動する駆動手段とを備え、可動部形成基板の可動部のミラー面側に回折格子が形成されてなり、第１のカバー基板は、入射光を透過させる入射光透過部、および、０次の回折光である反射光からなる走査光を透過させる走査光透過部が形成されるとともに、０次以外の規定次数の回折光を受光する受光素子が可動部形成基板側に設けられてなることを特徴とするＭＥＭＳ光スキャナ。   An outer frame formed by using a semiconductor substrate, arranged on the inner side of the outer frame part, the outer frame part and provided with a mirror surface on one surface side, and the outer frame arranged with the movable part sandwiched inside the outer frame part. A movable part forming substrate having a pair of torsion springs that can be deformed by connecting the movable part and the movable part, and a first cover substrate joined to one surface side of the movable part forming substrate on which the mirror surface is provided And a second cover substrate joined to the other surface side of the movable part forming substrate and a driving means for driving the movable part, and a diffraction grating is formed on the mirror surface side of the movable part of the movable part forming substrate. The first cover substrate is formed with an incident light transmitting portion that transmits incident light and a scanning light transmitting portion that transmits scanning light composed of reflected light that is zero-order diffracted light, and other than the zero-order. Receives diffracted light of specified order MEMS optical scanner, wherein the light receiving element is provided on the movable portion substrate side. 前記回折格子は、平面視において格子周期方向に直交する方向を、前記各捩りばね部の並設方向に対して非平行としてあることを特徴とする請求項１記載のＭＥＭＳ光スキャナ。   The MEMS optical scanner according to claim 1, wherein the diffraction grating has a direction orthogonal to the grating periodic direction in plan view that is not parallel to the parallel direction of the torsion spring portions. 前記回折格子は、前記可動部における前記ミラー面側に周期的な溝を設けることにより形成されてなることを特徴とする請求項１または請求項２記載のＭＥＭＳ光スキャナ。   The MEMS optical scanner according to claim 1, wherein the diffraction grating is formed by providing a periodic groove on the mirror surface side of the movable part. 前記回折格子は、溝形状が鋸歯状であることを特徴とする請求項１ないし請求項３のいずれか１項に記載のＭＥＭＳ光スキャナ。   The MEMS optical scanner according to any one of claims 1 to 3, wherein the diffraction grating has a sawtooth shape in a groove shape. 前記回折格子は、前記回折格子は、溝形状が矩形状であることを特徴とする請求項１ないし請求項３のいずれか１項に記載のＭＥＭＳ光スキャナ。   The MEMS optical scanner according to claim 1, wherein the diffraction grating has a rectangular groove shape. 前記回折格子は、相対的に反射率の高い材料からなるライン状の高反射率膜と相対的に反射率の低い材料からなるライン状の低反射率膜とが前記ミラー面に沿って交互に配列されてなることを特徴とする請求項１または請求項２記載のＭＥＭＳ光スキャナ。   The diffraction grating has a line-shaped high reflectance film made of a material having a relatively high reflectance and a line-shaped low reflectance film made of a material having a relatively low reflectance alternately along the mirror surface. 3. The MEMS optical scanner according to claim 1, wherein the MEMS optical scanner is arranged. 前記低反射率膜がＳｉＯ２膜からなり、前記高反射率膜が金属膜であることを特徴とする請求項６記載のＭＥＭＳ光スキャナ。 The low reflectance film is a SiO 2 film, MEMS optical scanner according to claim 6, wherein said high reflectivity film is characterized in that it is a metal film. 前記規定次数が−１であることを特徴とする請求項１ないし請求項７のいずれか１項に記載のＭＥＭＳ光スキャナ。   The MEMS optical scanner according to claim 1, wherein the specified order is −1. 前記第１のカバー基板は、前記走査光以外の回折光が外部へ出射するのを遮光する遮光膜が形成されてなることを特徴とする請求項１ないし請求項８のいずれか１項に記載のＭＥＭＳ光スキャナ。   9. The light shielding film according to claim 1, wherein the first cover substrate is formed with a light shielding film that shields diffracted light other than the scanning light from being emitted to the outside. MEMS optical scanner. 前記外側フレーム部と前記第１のカバー基板と前記第２のカバー基板とで囲まれた空間が真空雰囲気であることを特徴とする請求項１ないし請求項９のいずれか１項に記載のＭＥＭＳ光スキャナ。   10. The MEMS according to claim 1, wherein a space surrounded by the outer frame portion, the first cover substrate, and the second cover substrate is a vacuum atmosphere. Optical scanner.
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