JPH09148467A - Structure for vacuum-sealing working element and its manufacture - Google Patents
Structure for vacuum-sealing working element and its manufactureInfo
- Publication number
- JPH09148467A JPH09148467A JP32973895A JP32973895A JPH09148467A JP H09148467 A JPH09148467 A JP H09148467A JP 32973895 A JP32973895 A JP 32973895A JP 32973895 A JP32973895 A JP 32973895A JP H09148467 A JPH09148467 A JP H09148467A
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- Prior art keywords
- outer shell
- substrate
- vacuum
- operating element
- silicon oxide
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ジャイロや振動子
や共振子等に用いられる振動体や赤外線センサ等の動作
素子が真空封止された動作素子の真空封止の構造および
その製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for vacuum-sealing an operating element in which an operating element such as a vibrating body used for a gyro, a vibrator, a resonator, or an infrared sensor is vacuum-sealed, and a manufacturing method thereof. It is a thing.
【０００２】[0002]
【従来の技術】周知のように、近年において、マイクロ
マシニング技術を用いたマイクロジャイロや振動子や共
振子等の動作素子である振動体が作製されており、この
ような振動体は、空気のダンピングに起因した振動特性
の悪化を防止するために、次のような策が講じられてい
る。例えば、振動体を形成した基板面の上側に振動体を
覆う外殻を設け、この外殻の内部を真空空間とし、その
真空空間に前記振動体を収容封止し、前記空気のダンピ
ングに起因した振動特性の悪化を回避する策が講じられ
ている。このように振動体等を真空封止したものは真空
封止素子として知られており、また、前記外殻は多結晶
シリコンや窒化シリコンで形成されたものが知られてい
る。2. Description of the Related Art As is well known, in recent years, a vibrating body, which is an operating element such as a micro gyro, a vibrator or a resonator, has been manufactured by using a micromachining technique. The following measures have been taken in order to prevent the deterioration of vibration characteristics due to damping. For example, an outer shell that covers the vibrating body is provided above the surface of the substrate on which the vibrating body is formed, and the inside of the outer shell serves as a vacuum space, and the vibrating body is housed and sealed in the vacuum space. Measures are taken to avoid the deterioration of the vibration characteristics. Such a vacuum-sealed vibrating body is known as a vacuum-sealed element, and the outer shell made of polycrystalline silicon or silicon nitride is known.
【０００３】上記のように外殻を用して振動体を真空封
止した真空封止素子は、一般的に、次のように作製され
る。まず、マイクロマシニング技術を用いて基板面に振
動体および振動体を動作させるための導体パターンや電
極等を形成し、振動体が形成された基板面に振動体を覆
う犠牲層を積層形成する。さらに、その上側に、基板を
例えば600 ℃以上の高温に加熱した状態で多結晶シリコ
ン膜を、あるいは、800 ℃以上の高温に加熱した状態で
窒化シリコン膜を積層して外殻を形成する。そして、外
殻にエッチング液を犠牲層に浸入させるための貫通孔を
設け、この貫通孔からエッチング液を犠牲層に浸入させ
犠牲層をエッチング除去し、外殻の内部に空間を形成す
る。然る後、真空中で、前記外殻の内部の空間を真空排
気し、真空排気完了後、引き続き真空中で、前記貫通孔
を塞いで振動体を真空空間に収容封止し、振動体の真空
封止素子が完成する。A vacuum-sealed element in which the vibrating body is vacuum-sealed by using the outer shell as described above is generally manufactured as follows. First, a vibrating body and conductor patterns and electrodes for operating the vibrating body are formed on the surface of the substrate by using a micromachining technique, and a sacrificial layer covering the vibrating body is laminated on the surface of the substrate on which the vibrating body is formed. Further, an outer shell is formed by laminating a polycrystalline silicon film on the upper side of the substrate while heating the substrate to a high temperature of 600 ° C. or higher, or a silicon nitride film while heating the substrate to a high temperature of 800 ° C. or higher. Then, the outer shell is provided with a through hole for allowing the etching solution to penetrate into the sacrificial layer, the etching solution is allowed to penetrate into the sacrificial layer through the through hole, and the sacrificial layer is etched away to form a space inside the outer shell. After that, the space inside the outer shell is evacuated in a vacuum, and after the evacuation is completed, the through hole is closed in a vacuum, and the vibrating body is housed and sealed in the vacuum space. The vacuum sealing element is completed.
【０００４】[0004]
【発明が解決しようとする課題】上記のように、従来に
おいては、外殻を多結晶シリコンあるいは窒化シリコン
の膜で形成していた。外殻を多結晶シリコンで形成する
場合には、基板を600 ℃以上に加熱することから、基板
に形成されていた導体パターンや電極等のメタルとシリ
コンとの相互拡散現象が発生し、メタルが拡散してしま
うので導体パターンや電極が損傷してしまうという問題
や、基板に多結晶シリコンの外殻を設けた後の冷却で、
加熱された基板の温度と冷却後の基板の温度との差が激
しいことから、その温度差に応じ基板と多結晶シリコン
との熱膨張係数の差が大きく起因して外殻の内部応力が
非常に大きくなり、この内部応力の増大によって外殻が
歪んだり、外殻に亀裂が生じてしまうという問題があ
る。As described above, conventionally, the outer shell is formed of a film of polycrystalline silicon or silicon nitride. When the outer shell is made of polycrystalline silicon, the substrate is heated to 600 ° C or higher, which causes a mutual diffusion phenomenon between the metal such as the conductor pattern and electrodes formed on the substrate and silicon and the metal is not formed. The problem that the conductor pattern and electrodes are damaged because it diffuses, and the cooling after providing the outer shell of polycrystalline silicon on the substrate,
Since the difference between the temperature of the heated substrate and the temperature of the cooled substrate is large, the internal stress of the outer shell is extremely large due to the large difference in the coefficient of thermal expansion between the substrate and polycrystalline silicon due to the temperature difference. However, there is a problem that the outer shell is distorted or cracked due to the increase of the internal stress.
【０００５】また、多結晶シリコンは不透明であること
から、多結晶シリコンの外殻の下側に前記犠牲層が隠れ
てしまい、犠牲層のエッチング除去の際に、犠牲層のエ
ッチング除去が完了したか否かを目視により確認できな
いので、例えば実験等により求めたエッチング時間に基
づいてエッチング除去の終了のタイミングを図ってい
る。しかしながら、実験等により求めたエッチング時間
と実際のエッチング時間とが一致するとは限らず、実際
のエッチング時間の方が長くなると犠牲層が残ってしま
うという問題がある。さらに、多結晶シリコンは半導体
であることから、多結晶シリコンの外殻と振動体を動作
させるための電極との間に浮遊容量が発生してしまうの
で、ジャイロ等のように振動の変化を静電容量の変化に
よって検出する方式のセンサにあっては、検出静電容量
の信号中に前記浮遊容量がノイズとなって混入し、振動
体の容量変化を精度良く検出することができないという
問題がある。Since the polycrystalline silicon is opaque, the sacrificial layer is hidden under the outer shell of the polycrystalline silicon, and the sacrificial layer is completely removed by etching. Since it is not possible to visually confirm whether or not this is the case, the timing for ending the etching removal is set based on the etching time obtained by, for example, an experiment. However, the etching time obtained by experiments or the like does not always match the actual etching time, and there is a problem that the sacrificial layer remains if the actual etching time becomes longer. Further, since polycrystalline silicon is a semiconductor, stray capacitance is generated between the outer shell of polycrystalline silicon and the electrode for operating the vibrating body. In the sensor of the type that detects by the change of the capacitance, there is a problem that the stray capacitance is mixed in the signal of the detection capacitance as noise and the capacitance change of the vibrating body cannot be detected accurately. is there.
【０００６】外殻を窒化シリコンで形成する場合にも、
前記多結晶シリコン同様に、基板に窒化シリコンの外殻
を設ける際に基板を800 ℃以上の高温に加熱しなければ
ならず、基板に形成されていた導体パターンや電極等の
メタルとシリコンとの相互拡散現象が発生して導体パタ
ーンや電極が損傷してしまうという問題や、基板に窒化
シリコンの外殻を設けた後の冷却で、加熱された基板の
温度と冷却後の基板の温度が激しいことによる外殻の内
部応力の増大によって外殻が歪んだり、外殻に亀裂が生
じるという問題がある。When the outer shell is made of silicon nitride,
Like the polycrystalline silicon, the substrate must be heated to a high temperature of 800 ° C. or more when the outer shell of silicon nitride is provided on the substrate, and the metal such as the conductor pattern or the electrode formed on the substrate and the silicon are There is a problem that the mutual diffusion phenomenon occurs and the conductor pattern and electrodes are damaged, and the temperature of the heated substrate and the temperature of the substrate after cooling are high due to cooling after providing the outer shell of silicon nitride on the substrate. There is a problem that the outer shell is distorted or cracked due to the increase of the internal stress of the outer shell.
【０００７】本発明は上記課題を解決するためになされ
たものであり、その目的は、基板の高温加熱による導体
パターンや電極のメタルの拡散を回避して導体パターン
や電極の損傷を防止し、かつ、外殻形成後における外殻
の内部応力の増大に起因した外殻の歪みや亀裂の弊害を
なくし、かつ、外殻内部の犠牲層のエッチング除去を完
璧に行え、かつ、動作素子を動作させるための電極と外
殻との間に浮遊容量が発生しない動作素子の真空封止の
構造およびその製造方法を提供することにある。The present invention has been made to solve the above problems, and an object thereof is to prevent the metal of the conductor pattern or the electrode from diffusing due to high temperature heating of the substrate to prevent damage to the conductor pattern or the electrode. In addition, it eliminates the adverse effects of outer shell strain and cracks due to an increase in the inner stress of the outer shell after formation of the outer shell, and can completely remove the sacrificial layer inside the outer shell by etching, and operates the operating element. It is to provide a structure for vacuum sealing an operating element in which no stray capacitance is generated between an electrode for causing it and an outer shell, and a manufacturing method thereof.
【０００８】[0008]
【課題を解決するための手段】上記目的を達成するため
に、本発明は次のような構成をもって前記課題を解決す
るための手段としている。すなわち、本発明の動作素子
の真空封止の構造は、基板の素子形成面に動作素子が形
成され、この動作素子の形成領域の上側は外殻によって
覆われて、外殻の内部は真空空間と成し、前記動作素子
が前記外殻の真空空間内に収容封止されており、前記外
殻は酸化シリコンを主成分とした膜で形成されている構
成をもって前記課題を解決する手段としている。また、
上記動作素子の真空封止の構造は、動作素子は振動体で
あることも前記課題を解決する特徴的な手段としてい
る。In order to achieve the above-mentioned object, the present invention has the following structure to solve the above-mentioned problems. That is, according to the vacuum sealing structure of the operating element of the present invention, the operating element is formed on the element forming surface of the substrate, the upper side of the operating element forming region is covered with the outer shell, and the inside of the outer shell is the vacuum space. The operating element is housed and sealed in the vacuum space of the outer shell, and the outer shell is formed of a film containing silicon oxide as a main component, which is a means for solving the above problems. . Also,
The vacuum-sealed structure of the operating element is also a characteristic means for solving the above-mentioned problem that the operating element is a vibrating body.
【０００９】さらに本発明の動作素子の真空封止の構造
の製造方法は、基板の素子形成面に動作素子を形成し、
その動作素子および該動作素子の近傍の基板面の上側に
犠牲層を積層形成し、次に、その犠牲層の上側に酸化シ
リコンを主成分とする外殻を積層形成し、然る後に、前
記動作素子の近傍の基板面上の位置で外殻に貫通孔を形
成し、次に、この貫通孔から犠牲層にエッチング液を浸
入させ犠牲層をエッチング除去して外殻の内部に空間を
形成し、真空空間の雰囲気中で前記貫通孔を閉鎖して外
殻の内部を動作素子収容の真空空間とする構成をもって
前記課題を解決する手段としている。Further, according to the method of manufacturing a vacuum-sealed structure of an operating element of the present invention, the operating element is formed on the element forming surface of the substrate,
A sacrificial layer is laminated and formed on the operating element and a substrate surface near the operating element, and then an outer shell containing silicon oxide as a main component is laminated and formed on the sacrificial layer. A through hole is formed in the outer shell at a position on the substrate surface in the vicinity of the operating element, and then an etching solution is introduced into the sacrificial layer through the through hole to remove the sacrificial layer by etching to form a space inside the outer shell. However, the structure is such that the through hole is closed in the atmosphere of the vacuum space and the inside of the outer shell serves as a vacuum space for accommodating the operating element, which is a means for solving the above problem.
【００１０】上記構成の発明において、外殻を酸化シリ
コンを主成分とする膜で形成することから、外殻の形成
時に、基板は酸化シリコンを主成分とする膜の形成に適
した250 ℃以下の温度に加熱される。このように基板は
250 ℃以下の温度に加熱されるので、すでに基板に形成
されていた導体パターンや電極等のメタルの拡散現象は
発生せず、メタルの拡散に起因した導体パターンや電極
の損傷が防止される。また、上記基板の加熱温度と外殻
を形成して冷却した後の基板の温度との差が小さいの
で、外殻を形成した後の基板の冷却で外殻の内部応力の
増大が回避され、内部応力の増大による外殻の歪みや亀
裂の弊害がなくなる。In the invention of the above structure, since the outer shell is formed of a film containing silicon oxide as a main component, the substrate is 250 ° C. or less suitable for forming a film containing silicon oxide as a main component when the outer shell is formed. Is heated to the temperature of. In this way the substrate
Since it is heated to a temperature of 250 ° C. or less, the diffusion phenomenon of the metal such as the conductor pattern and the electrode already formed on the substrate does not occur, and the damage of the conductor pattern and the electrode due to the diffusion of the metal is prevented. Further, since the difference between the heating temperature of the substrate and the temperature of the substrate after forming and cooling the outer shell is small, an increase in internal stress of the outer shell is avoided by cooling the substrate after forming the outer shell, The adverse effects of strain and cracks on the outer shell due to the increase in internal stress are eliminated.
【００１１】また、酸化シリコンを主成分とする膜によ
り形成された外殻は透明であることから、外殻内部の犠
牲層のエッチング除去の際に、犠牲層のエッチング除去
の進行状況を外殻を透して確認することが可能で、エッ
チング除去の完了を目視により確認してからエッチング
除去工程を終了させることによって、エッチング除去さ
れなかった犠牲層が外殻内部に残ってしまうということ
が回避される。Further, since the outer shell formed of the film containing silicon oxide as a main component is transparent, the progress of the etching removal of the sacrificial layer is controlled when the sacrificial layer inside the outer shell is removed by etching. By confirming the completion of etching removal visually and then ending the etching removal process, it is possible to avoid that the sacrificial layer that has not been removed by etching remains inside the outer shell. To be done.
【００１２】さらに、酸化シリコンを主成分とする外殻
は絶縁体であるので、外殻と動作素子を動作させるため
の電極との間に浮遊容量は発生せず、静電容量の変化を
利用したセンサとしての動作素子の容量変化は、浮遊容
量に起因したノイズに妨害されずに、精度良く検出され
る。Furthermore, since the outer shell containing silicon oxide as a main component is an insulator, no stray capacitance is generated between the outer shell and the electrode for operating the operating element, and the change in electrostatic capacitance is utilized. The capacitance change of the operating element as the sensor is accurately detected without being disturbed by noise caused by the stray capacitance.
【００１３】[0013]
【発明の実施の形態】以下に、本発明の実施の形態例を
図面に基づいて説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１４】図１の（ａ）には本発明に係る動作素子の
真空封止の構造における一実施の形態例の斜視図が、図
１の（ｂ）には図１の（ａ）におけるＡ−Ａ断面図がそ
れぞれ示されており、この動作素子の真空封止の構造
は、基板６と、ジャイロや振動子や共振子等として用い
られる振動体（動作素子）２と、酸化シリコン膜10ａ，
10ｂから成る外殻３とを有して構成されている。FIG. 1A is a perspective view of an embodiment of the vacuum sealing structure of the operating element according to the present invention, and FIG. 1B is a perspective view of FIG. 1A. -A cross-sectional views are respectively shown, and the vacuum sealing structure of this operating element includes a substrate 6, a vibrating body (operating element) 2 used as a gyro, a vibrator, a resonator or the like, and a silicon oxide film 10a. ，
And an outer shell 3 made of 10b.
【００１５】同図の（ａ）および（ｂ）に示すように、
基板６の振動体形成面（素子形成面）12にはマイクロマ
シニング技術等を用いて振動体２が形成され、この振動
体２を覆うように外殻３が設けられている。上記外殻３
は、前記の如く、酸化シリン膜10ａ，10ｂにより形成さ
れており、絶縁体、かつ、透明、かつ、形成時に基板６
を250 ℃以下の温度に加熱して作製されるものであり、
この外殻３の内部は振動体２の収容空間８を成し、振動
体２が収容空間８に収容されている。前記収容空間８は
振動体２の振動に邪魔にならない大きさを有し、振動体
２の振動特性が良好となる真空状態（例えば約0.3 Ｐ
ａ）に真空封止されている。As shown in (a) and (b) of FIG.
The vibrating body 2 is formed on the vibrating body forming surface (element forming surface) 12 of the substrate 6 by using a micromachining technique or the like, and the outer shell 3 is provided so as to cover the vibrating body 2. Outer shell 3
As described above, it is formed of the silicin oxide films 10a and 10b, is an insulator and is transparent, and the substrate 6 is formed at the time of formation.
Is produced by heating to a temperature of 250 ℃ or less,
The inside of the outer shell 3 forms a housing space 8 for the vibrating body 2, and the vibrating body 2 is housed in the housing space 8. The accommodating space 8 has a size that does not interfere with the vibration of the vibrating body 2, and is in a vacuum state (for example, about 0.3 P) in which the vibrating body 2 has good vibration characteristics.
Vacuum sealed in a).
【００１６】また、上記収容空間８を形成している酸化
シリコン膜10ａには製造の便宜上設けられた複数の貫通
孔（エッチホール）７が形成されており、この貫通孔７
には酸化シリコン膜10ｂの材料が入り込んで貫通孔７を
完全に閉鎖している。なお、図示されていないが、基板
６には振動体２を動作させるための導体パターンや電極
が形成されている。Further, a plurality of through holes (etch holes) 7 provided for the convenience of manufacturing are formed in the silicon oxide film 10a forming the accommodation space 8. The through holes 7
The material of the silicon oxide film 10b enters in to completely close the through hole 7. Although not shown, the substrate 6 is provided with conductor patterns and electrodes for operating the vibrating body 2.
【００１７】以下に、上記のように酸化シリコン膜10
ａ，10ｂで外殻を形成した動作素子（振動体２）の真空
封止の構造の製造方法における一実施の形態例を図２に
基づいて説明する。まず、同図の（ａ）に示すように、
基板６の振動体形成面12にマイクロマシニング技術等を
用いて振動体２を、また、振動体２を動作させるための
導体パターン（図示せず）や電極（図示せず）をそれぞ
れ形成し、同図の（ｂ）に示すように、酸化亜鉛等の犠
牲層５ａを振動体２および該振動体２の近傍の基板面12
の上側に積層形成する。この犠牲層５ａは図１の（ｂ）
に示すような振動体２の収容空間８の大部分を形成する
ためのものである。その犠牲層５ａの上側に、同図の
（ｃ）に示すように、酸化亜鉛等の犠牲層５ｂを、この
犠牲層５ｂから引き出された犠牲層（エッチチャンネ
ル）５ｃを基板６の面上にそれぞれ積層形成する。上記
のように、犠牲層５ａと犠牲層５ｂ，５ｃとを分けて形
成することによって、犠牲層５ｃの厚みを犠牲層５ａよ
りも薄く形成することが可能となる。Below, as described above, the silicon oxide film 10 is formed.
An embodiment of a method for manufacturing a vacuum-sealed structure of an operating element (vibrating body 2) having an outer shell formed by a and 10b will be described with reference to FIG. First, as shown in FIG.
The vibrating body 2 is formed on the vibrating body forming surface 12 of the substrate 6 by using a micromachining technique or the like, and a conductor pattern (not shown) or an electrode (not shown) for operating the vibrating body 2 is formed. As shown in FIG. 3B, the sacrificial layer 5a made of zinc oxide or the like is provided on the vibrating body 2 and the substrate surface 12 near the vibrating body 2.
Is formed on the upper side of. This sacrificial layer 5a is shown in FIG.
It is for forming most of the accommodation space 8 of the vibrating body 2 as shown in FIG. On the upper side of the sacrificial layer 5a, a sacrificial layer 5b of zinc oxide or the like and a sacrificial layer (etch channel) 5c extracted from the sacrificial layer 5b are formed on the surface of the substrate 6 as shown in FIG. Each is laminated. As described above, by forming the sacrificial layer 5a and the sacrificial layers 5b and 5c separately, the sacrificial layer 5c can be formed to be thinner than the sacrificial layer 5a.
【００１８】さらに、同図の（ｄ）に示すように、犠牲
層５ｂ，５ｃとその近傍の振動体形成面12の上側に、ス
パッタ法やＣＶＤ法により酸化シリコン膜10ａを積層形
成（成膜）する。この酸化シリコン膜10ａを例えば複数
種あるスパッタ法のうちのＲＦスパッタ法を用いて成膜
するときには、基板６を約120 ℃に加熱して成膜が行わ
れる。また、酸化シリコン膜10ａを上記以外のスパッタ
法やＣＶＤ法を用いて成膜するときには基板６を酸化シ
リコン膜10ａの成膜に適した250 ℃以下の高温度に加熱
して成膜が行われる。Further, as shown in (d) of the same figure, a silicon oxide film 10a is formed (deposited) on the sacrifice layers 5b and 5c and the vibrating body forming surface 12 in the vicinity thereof by sputtering or CVD. ) Do. When the silicon oxide film 10a is formed by using, for example, the RF sputtering method out of a plurality of kinds of sputtering methods, the substrate 6 is heated to about 120 ° C. to form the film. When the silicon oxide film 10a is formed by a sputtering method or a CVD method other than the above, the substrate 6 is heated to a high temperature of 250 ° C. or lower suitable for forming the silicon oxide film 10a. .
【００１９】次に、同図の（ｅ）に示すように、犠牲層
（エッチチャンネル）５ｃの上側に形成された酸化シリ
コン膜10ａ、つまり、振動体２の近傍の基板面上の位置
の酸化シリコン膜10ａに犠牲層５ｃに達する貫通孔（エ
ッチホール）７をＲＩＥ（反応イオンエッチング）等を
用いて形成する。そして、上記貫通孔７からエッチング
液（エッチャント）を浸入させる。このエッチング液は
犠牲層５ａ，５ｂ，５ｃをエッチングするが、酸化シリ
コン膜10ａはエッチングしないものであり、例えば、犠
牲層５ａ，５ｂ，５ｃが酸化亜鉛で形成されているとき
には、酸化亜鉛をエッチングし、かつ、酸化シリコンは
エッチングしない希塩酸がエッチング液として使用され
る。Next, as shown in (e) of the figure, the silicon oxide film 10a formed on the upper side of the sacrificial layer (etch channel) 5c, that is, the position of the substrate 2 near the vibrating body 2 is oxidized. A through hole (etch hole) 7 reaching the sacrificial layer 5c is formed in the silicon film 10a by using RIE (reactive ion etching) or the like. Then, an etching solution (etchant) is made to infiltrate through the through hole 7. This etching solution etches the sacrificial layers 5a, 5b, 5c but does not etch the silicon oxide film 10a. For example, when the sacrificial layers 5a, 5b, 5c are made of zinc oxide, the zinc oxide is etched. However, dilute hydrochloric acid that does not etch silicon oxide is used as an etching solution.
【００２０】前記貫通孔７から浸入したエッチング液
は、犠牲層５ｃから５ｂ，５ａへとエッチング除去して
いき、同図の（ｆ）に示すように、振動体２の収容空間
８を酸化シリコン膜10ａの内部に形成する。このエッチ
ング除去工程の際、酸化シリコン膜10ａは透明であるの
で、酸化シリコン膜10ａを透して犠牲層５ａ，５ｂ，５
ｃのエッチング除去の進行状況を目視により確認するこ
とが可能で、犠牲層５ａ，５ｂ，５ｃが完全にエッチン
グ除去されたのを目視により確認した後に次の工程へと
進む。The etching liquid that has penetrated from the through holes 7 is removed by etching from the sacrificial layers 5c to 5b and 5a, and as shown in FIG. It is formed inside the film 10a. At the time of this etching removal step, since the silicon oxide film 10a is transparent, the sacrifice layers 5a, 5b, 5 are penetrated through the silicon oxide film 10a.
It is possible to visually confirm the progress of etching removal of c, and after visually confirming that the sacrificial layers 5a, 5b, and 5c have been completely removed by etching, proceed to the next step.
【００２１】次の工程では、同図の（ｆ）に示す基板６
を酸化シリコン膜の成膜装置（真空装置）の排気室内に
設置して、前記排気室内の真空排気を行うと共に、貫通
孔７から振動体２の収容空間８の空気を排気し、排気室
および収容空間８を振動体２の振動特性が良好となり、
かつ、酸化シリコン膜の成膜に適切な真空状態（例えば
ＲＦスパッタ法を用いて酸化シリコン膜の成膜を行う場
合には約0.3 Ｐａ）にする。そして、排気室および収容
空間８を完全に真空排気した後、引き続き排気室および
収容空間８の真空が維持され、基板６が酸化シリコンの
成膜に適した温度（250 ℃以下）に加熱された状態で、
同図の（ｇ）に示すように、酸化シリコン膜10ａの上に
スパッタ法やＣＶＤ法を用いて酸化シリコン膜10ｂを成
膜して酸化シリコン膜10ａ，10ｂから成る外殻３が完成
されると共に、上記酸化シリコン膜10ｂの材料が貫通孔
７に入り込んで貫通孔７を塞ぎ（閉鎖し）振動体２が収
容空間８に真空封止されて振動体２の真空封止が完成す
る。In the next step, the substrate 6 shown in FIG.
Is installed in an exhaust chamber of a silicon oxide film forming apparatus (vacuum device) to evacuate the exhaust chamber, and at the same time, exhaust air in the accommodation space 8 of the vibrating body 2 from the through hole 7, The vibration characteristics of the vibrating body 2 are improved in the accommodation space 8,
In addition, a vacuum state suitable for forming the silicon oxide film (for example, about 0.3 Pa when forming the silicon oxide film by using the RF sputtering method) is set. Then, after the exhaust chamber and the accommodation space 8 were completely evacuated, the vacuum of the exhaust chamber and the accommodation space 8 was continuously maintained, and the substrate 6 was heated to a temperature (250 ° C. or lower) suitable for film formation of silicon oxide. In the state
As shown in (g) of the figure, a silicon oxide film 10b is formed on the silicon oxide film 10a by a sputtering method or a CVD method to complete the outer shell 3 composed of the silicon oxide films 10a and 10b. At the same time, the material of the silicon oxide film 10b enters the through hole 7 to close (close) the through hole 7, and the vibrating body 2 is vacuum-sealed in the accommodation space 8 to complete the vacuum sealing of the vibrating body 2.
【００２２】上記実施の形態例によれば、外殻３を酸化
シリコン膜10ａ，10ｂにより形成したので、酸化シリコ
ン膜10ａ，10ｂの成膜時に、基板６を酸化シリコン膜10
ａ，10ｂの成膜に適した250 ℃以下の温度に加熱するだ
けでよく、つまり、基板６を例えば600 ℃以上という高
温に加熱する必要がなく、基板を成膜に適した温度まで
加熱するのに要する時間が短くて済むし、基板６の高温
加熱に起因した導体パターンや電極のメタルの拡散が回
避され、導体パターンや電極が損傷してしまうのを防止
することができる。また、上記の如く、基板６を600 ℃
以上の高温に加熱する必要がなく、基板６を250 ℃以下
の温度に加熱して酸化シリコン膜10ａ又は10ｂを成膜す
ることから、基板の加熱温度と冷却した後の基板の温度
との差が小さく、酸化シリコン膜10ａ，10ｂの成膜終了
後の冷却で、酸化シリコン膜10ａ，10ｂの内部応力の増
大が回避されて内部応力の増大による酸化シリコン膜10
ａ，10ｂの歪みや亀裂が発生せずに、酸化シリコン膜10
ａ，10ｂ、つまり、外殻３の機械的強度を強くすること
ができる。According to the above-described embodiment, the outer shell 3 is formed of the silicon oxide films 10a and 10b. Therefore, when the silicon oxide films 10a and 10b are formed, the substrate 6 is covered with the silicon oxide film 10a.
It is only necessary to heat to a temperature of 250 ° C. or lower suitable for film formation of a and 10b, that is, it is not necessary to heat the substrate 6 to a high temperature of, for example, 600 ° C. or higher, and the substrate is heated to a temperature suitable for film formation. The time required for this is short, the diffusion of the metal of the conductor pattern and the electrode due to the high temperature heating of the substrate 6 is avoided, and the conductor pattern and the electrode can be prevented from being damaged. Also, as described above, the substrate 6 is heated to 600 ° C.
Since it is not necessary to heat to the above high temperature and the substrate 6 is heated to a temperature of 250 ° C. or lower to form the silicon oxide film 10a or 10b, the difference between the heating temperature of the substrate and the temperature of the substrate after cooling is obtained. Is small, the increase in internal stress of the silicon oxide films 10a and 10b is avoided by cooling after the formation of the silicon oxide films 10a and 10b, and the silicon oxide film 10 due to the increase in internal stress is avoided.
Silicon oxide film 10 without distortion or cracking of a and 10b
a, 10b, that is, the mechanical strength of the outer shell 3 can be increased.
【００２３】さらに、酸化シリコン膜10ａは透明である
ことから、犠牲層５ａ，５ｂ，５ｃのエッチング除去の
際に、そのエッチング除去の完了を酸化シリコン膜10ａ
を透して目視により確認してエッチング除去工程の終了
を決定でき、犠牲層５ａ，５ｂ，５ｃが完全にエッチン
グ除去しきれずに残ってしまうという従来の問題を解決
することができる。Further, since the silicon oxide film 10a is transparent, when the sacrifice layers 5a, 5b, 5c are removed by etching, the completion of the etching removal is completed by the silicon oxide film 10a.
Thus, it is possible to determine the end of the etching removal step by visually observing through, and it is possible to solve the conventional problem that the sacrificial layers 5a, 5b, 5c are not completely removed by etching and remain.
【００２４】さらにまた、酸化シリコン膜10ａ，10ｂは
絶縁体であることから、酸化シリコン膜10ａ，10ｂと振
動体２を動作させるための電極との間に浮遊容量が発生
せず、振動体２がジャイロのように静電容量の変化を利
用するセンサである場合に、前記浮遊容量に起因した振
動体２の容量変化の検出精度の悪化を回避することがで
き、振動体２の容量変化の検出精度を高めるという優れ
た効果を奏することができる。Furthermore, since the silicon oxide films 10a and 10b are insulators, no stray capacitance is generated between the silicon oxide films 10a and 10b and the electrodes for operating the vibrator 2, and the vibrator 2 is not generated. Is a sensor such as a gyro that utilizes a change in capacitance, it is possible to avoid deterioration in detection accuracy of a change in capacitance of the vibrating body 2 due to the stray capacitance, and An excellent effect of increasing detection accuracy can be achieved.
【００２５】なお、本発明は上記実施の形態例に限定さ
れるものではなく、様々な実施の形態を採り得る。例え
ば、上記実施の形態例では、動作素子として振動体を例
にして説明したが、赤外線センサのように振動しない動
作素子においても上記実施の形態例同様に真空封止して
もよい。このように、動作素子を真空封止することによ
って、長期間空気に晒されることによる素子の劣化を防
止することができるし、空気の対流による影響を防止で
きる。また、上記実施の形態例では、外殻３は純粋な酸
化シリコンの膜で形成されていたが、酸化シリコンを主
成分として多少の不純物を含む膜、つまり、ほぼ透明か
つ絶縁体で、成膜時にメタルの拡散現象や外殻の歪みや
亀裂を発生させない温度に基板を加熱して成膜可能な膜
で形成すればよく、純粋な酸化シリコン膜と限定される
ものではない。It should be noted that the present invention is not limited to the above-described embodiment, but can adopt various embodiments. For example, although the vibrating body has been described as an example of the operating element in the above-described embodiment, an operating element that does not vibrate such as an infrared sensor may be vacuum-sealed as in the above-described embodiment. As described above, by vacuum-sealing the operating element, it is possible to prevent the element from being deteriorated due to being exposed to air for a long period of time, and to prevent the influence of air convection. Further, in the above-described embodiment, the outer shell 3 is formed of a pure silicon oxide film, but a film containing silicon oxide as a main component and some impurities, that is, an almost transparent and insulating film is formed. It is sufficient to heat the substrate to a temperature at which a metal diffusion phenomenon or outer shell distortion or crack does not occur, so that the film can be formed into a film, and the film is not limited to a pure silicon oxide film.
【００２６】さらに、上記実施の形態例では、貫通孔７
を酸化シリコン膜10ｂにより閉鎖していたが、別の閉鎖
材を用いて閉鎖してもよく、このような場合には外殻３
を酸化シリコン膜10ａと10ｂとに分けて形成しなくても
よい。Further, in the above embodiment, the through hole 7
Was closed by the silicon oxide film 10b, but it may be closed by using another closing material. In such a case, the outer shell 3
Need not be formed separately for the silicon oxide films 10a and 10b.
【００２７】[0027]
【発明の効果】本発明は、外殻を酸化シリコンを主成分
とする膜で形成しており、この酸化シリコンを主成分と
する膜はその膜の形成に適した250 ℃以下に基板を加熱
して形成できることから、外殻を多結晶シリコンや窒化
シリコンで形成するときのように、動作素子や、該動作
素子を動作させるための導体パターンや電極等が設けら
れている基板を600 ℃以上の高温に加熱する必要がな
く、基板の高温加熱に起因した導体パターンや電極のメ
タルの拡散が回避され、メタルの拡散による導体パター
ンや電極の損傷を防止できる。According to the present invention, the outer shell is formed of a film containing silicon oxide as a main component, and the film containing silicon oxide as a main component heats the substrate to 250 ° C. or lower suitable for forming the film. Therefore, as in the case of forming the outer shell with polycrystalline silicon or silicon nitride, the operating element and the substrate on which the conductor pattern and electrodes for operating the operating element are provided are 600 ° C or more. Since it is not necessary to heat the substrate to a high temperature, the diffusion of the metal of the conductor pattern or the electrode due to the high temperature heating of the substrate can be avoided, and the conductor pattern or the electrode can be prevented from being damaged by the diffusion of the metal.
【００２８】また、上記の如く、基板を250 ℃以下に加
熱して外殻を形成できるので、加熱されたときの基板の
温度と冷却した後の基板の温度との差が小さく、その温
度差に応じた外殻の内部応力の増加は非常に小さくて済
み、内部応力の増大による外殻の歪みや亀裂の発生を抑
えることができる。Further, as described above, since the outer shell can be formed by heating the substrate to 250 ° C. or less, the difference between the temperature of the substrate when heated and the temperature of the substrate after cooling is small, and the temperature difference between them is small. The increase of the internal stress of the outer shell according to the above is very small, and it is possible to suppress the occurrence of strain or crack of the outer shell due to the increase of the internal stress.
【００２９】さらに、酸化シリコンを主成分とする膜は
透明であることから、外殻の内部の犠牲層のエッチング
除去の際に、犠牲層のエッチング除去の進行状況を外殻
を透して目視により確認することが可能であり、エッチ
ング除去の完了を目視により確認してエッチング除去工
程の終了を決定することによって、エッチング除去しき
れなかった犠牲層が残ってしまうという問題を確実に回
避することができる。Further, since the film containing silicon oxide as a main component is transparent, when the sacrificial layer inside the outer shell is removed by etching, the progress of the etching removal of the sacrificial layer is visually observed through the outer shell. By confirming the completion of the etching removal visually and deciding the end of the etching removal process, it is possible to surely avoid the problem that the sacrificial layer that could not be completely removed remains. You can
【００３０】さらにまた、酸化シリコンを主成分とする
膜は絶縁体であることから、外殻と、動作素子を動作さ
せるための電極との間に浮遊容量は発生せず、動作素子
が静電容量の変化を利用するセンサ等の場合に、前記浮
遊容量によるノイズがないので、容量変化を精度良く検
出することが可能となるという優れた効果を奏するもの
である。Furthermore, since the film containing silicon oxide as the main component is an insulator, no stray capacitance is generated between the outer shell and the electrode for operating the operating element, and the operating element is electrostatically charged. In the case of a sensor or the like that uses a change in capacitance, since there is no noise due to the stray capacitance, it is possible to detect the change in capacitance with an excellent effect.
【図１】本発明に係る動作素子の真空封止の構造の一実
施の形態例を示す説明図である。FIG. 1 is an explanatory diagram showing an example of an embodiment of a structure for vacuum sealing an operating element according to the present invention.
【図２】本発明に係る動作素子の真空封止の構造の製造
方法における一実施の形態例を示す説明図である。FIG. 2 is an explanatory diagram showing an example of an embodiment of a method for manufacturing a vacuum-sealed structure of an operating element according to the present invention.
２ 振動体 ３ 外殻 ５ａ，５ｂ，５ｃ 犠牲層 ６ 基板 ７ 貫通孔 ８ 収容空間 10ａ，10ｂ 酸化シリコン膜 2 Vibrating body 3 Outer shell 5a, 5b, 5c Sacrificial layer 6 Substrate 7 Through hole 8 Storage space 10a, 10b Silicon oxide film
Claims (3)
れ、この動作素子の形成領域の上側は外殻によって覆わ
れて、外殻の内部は真空空間と成し、前記動作素子が前
記外殻の真空空間内に収容封止されており、前記外殻は
酸化シリコンを主成分とした膜で形成されていることを
特徴とする動作素子の真空封止の構造。1. An operating element is formed on an element forming surface of a substrate, an upper side of a region where the operating element is formed is covered with an outer shell, the inside of the outer shell forms a vacuum space, and the operating element is the outer space. A vacuum sealing structure for an operating element, wherein the shell is housed and sealed in a vacuum space, and the outer shell is formed of a film containing silicon oxide as a main component.
る請求項１記載の動作素子の真空封止の構造。2. The vacuum-sealed structure of the operating element according to claim 1, wherein the operating element is a vibrating body.
その動作素子および該動作素子の近傍の基板面の上側に
犠牲層を積層形成し、次に、その犠牲層の上側に酸化シ
リコンを主成分とする外殻を積層形成し、然る後に、前
記動作素子の近傍の基板面上の位置で外殻に貫通孔を形
成し、次に、この貫通孔から犠牲層にエッチング液を浸
入させ犠牲層をエッチング除去して外殻の内部に空間を
形成し、真空空間の雰囲気中で前記貫通孔を閉鎖して外
殻の内部を動作素子収容の真空空間とすることを特徴と
する動作素子の真空封止の構造の製造方法。3. An operating element is formed on an element formation surface of a substrate,
A sacrificial layer is laminated and formed on the operating element and a substrate surface near the operating element, and then an outer shell containing silicon oxide as a main component is laminated and formed on the sacrificial layer. A through hole is formed in the outer shell at a position on the substrate surface in the vicinity of the operating element, and then an etching solution is introduced into the sacrificial layer through the through hole to remove the sacrificial layer by etching to form a space inside the outer shell. Then, the through hole is closed in the atmosphere of the vacuum space to make the inside of the outer shell a vacuum space for accommodating the operating element, the method for manufacturing a vacuum sealing structure of the operating element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32973895A JPH09148467A (en) | 1995-11-24 | 1995-11-24 | Structure for vacuum-sealing working element and its manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32973895A JPH09148467A (en) | 1995-11-24 | 1995-11-24 | Structure for vacuum-sealing working element and its manufacture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09148467A true JPH09148467A (en) | 1997-06-06 |
Family
ID=18224731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32973895A Pending JPH09148467A (en) | 1995-11-24 | 1995-11-24 | Structure for vacuum-sealing working element and its manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09148467A (en) |
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| JP2001237334A (en) * | 1999-12-15 | 2001-08-31 | Asulab Sa | Method of airtightly encapsulating microsystem in situ |
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