JPH11337403A - Infrared detecting element and its manufacture - Google Patents
Infrared detecting element and its manufactureInfo
- Publication number
- JPH11337403A JPH11337403A JP14136298A JP14136298A JPH11337403A JP H11337403 A JPH11337403 A JP H11337403A JP 14136298 A JP14136298 A JP 14136298A JP 14136298 A JP14136298 A JP 14136298A JP H11337403 A JPH11337403 A JP H11337403A
- Authority
- JP
- Japan
- Prior art keywords
- infrared detecting
- infrared
- detecting element
- insulating film
- base frame
- Prior art date
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- Radiation Pyrometers (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、赤外線検出素子お
よび赤外線検出素子の製造方法に関する。[0001] 1. Field of the Invention [0002] The present invention relates to an infrared detecting element and a method of manufacturing the infrared detecting element.
【０００２】[0002]
【従来の技術】一般に赤外線検出素子は、非接触の温度
計として物体の検出や、特殊環境下における温度計測な
どに使用されている。最近の赤外線検出素子には、シリ
コンのマイクロマシーニング技術を用いて熱容量が小さ
く熱抵抗の大きな熱分離構造を形成し、その熱分離構造
部に赤外線検知領域を備え、入射する赤外線の吸収によ
る赤外線検知領域の温度上昇を、サーモパイルで検知す
る方式がある。このような赤外線検出素子はその検出信
号の処理回路等とともに一体のＩＣチップとして製造す
ることができる。2. Description of the Related Art Generally, an infrared detecting element is used as a non-contact thermometer for detecting an object or measuring temperature in a special environment. Recent infrared detectors use a silicon micromachining technology to form a thermal isolation structure with low heat capacity and high thermal resistance.The thermal isolation structure has an infrared detection area, which absorbs infrared radiation that enters. There is a method of detecting a temperature rise in a detection area by a thermopile. Such an infrared detecting element can be manufactured as an integrated IC chip together with a detection signal processing circuit and the like.
【０００３】図９に従来の赤外線検出素子を示す。
（ａ）は平面図、（ｂ）は（ａ）のＤ−Ｄ断面図、
（ｃ）は（ａ）のＥ−Ｅ断面図である。赤外線検出素子
は、その全体平面形状が四角形のシリコン基板１に梁２
２を介して赤外線検知領域２３を支持し、梁上にサーモ
パイルを形成して構成されている。シリコン基板１はそ
の上面が外周の各辺に沿ってポリシリコンエッチングス
トッパ４で幅寸法を画定された基枠５とされ、基枠５の
内面は四角錐状の凹部となっている。FIG. 9 shows a conventional infrared detecting element.
(A) is a plan view, (b) is a DD sectional view of (a),
(C) is EE sectional drawing of (a). The infrared detecting element has a beam 2 formed on a silicon substrate 1 having a square planar shape as a whole.
The infrared detection area 23 is supported via the second member 2 and a thermopile is formed on the beam. The upper surface of the silicon substrate 1 is a base frame 5 whose width is defined by a polysilicon etching stopper 4 along each side of the outer periphery, and the inner surface of the base frame 5 is a quadrangular pyramid-shaped recess.
【０００４】基枠５の各角部近傍からは隣接する辺に平
行に、かつ所定幅の間隙を設けてシリコン窒化膜の梁２
２がいずれも同方向に隣の梁近傍まで延びている。各梁
２２の内側には、各梁との間に所定の間隙を設けて同じ
くシリコン窒化膜の四角形の赤外線検知領域２３が設け
られ、その４つの角部がそれぞれ各梁２２の先端に接続
している。[0006] From the vicinity of each corner of the base frame 5, a beam of silicon nitride film 2 is provided in parallel with the adjacent side and with a predetermined width.
2 extend in the same direction to the vicinity of the adjacent beam. Inside each of the beams 22, a rectangular infrared detection region 23 of the same silicon nitride film is provided with a predetermined gap between each of the beams 22. The four corners are connected to the tips of the respective beams 22. ing.
【０００５】赤外線検知領域２３上には赤外線吸収膜７
が形成され、各梁上にはその全長にわたってサーモパイ
ルが設けられている。サーモパイルは、ｐ型ポリシリコ
ンとｎ型ポリシリコンからなり、ｐ型ポリシリコンサー
モパイル８、８’が互いに対向し、ｎ型ポリシリコンサ
ーモパイル９、９’が互いに対向するように配置されて
いる。そして、各サーモパイル間をアルミ配線１０が接
続している。On the infrared detecting area 23, an infrared absorbing film 7 is provided.
Is formed, and a thermopile is provided on each beam over its entire length. The thermopile is made of p-type polysilicon and n-type polysilicon, and is arranged so that p-type polysilicon thermopiles 8 and 8 'face each other and n-type polysilicon thermopiles 9 and 9' face each other. Then, an aluminum wiring 10 is connected between the thermopiles.
【０００６】図９の（ｂ）に示すように、赤外線検知領
域２３は梁２２によってシリコン基板１の四角錐状の凹
部空間内に支持されている。[0009] As shown in FIG. 9 (b), the infrared detecting region 23 is supported by a beam 22 in a quadrangular pyramid-shaped concave space of the silicon substrate 1.
【０００７】このような構成による赤外線検出素子の性
能評価は比検出能Ｄ＊ により説明される。比検出能Ｄ
＊ は、赤外線入力があったときのＳ／Ｎ比であり、式
（１）で表される。 Ｄ＊ ＝｛Ｓ×（Ａｄ×△ｆ）０．５ ｝／（Ｎ×Ｐ） （１） 但し、Ｓ：赤外線検出信号 Ｎ：赤外線検出信号に含まれるノイズ信号 Ｐ：赤外線入射エネルギー Ａｄ：赤外線検知領域の面積 Δｆ：周波数帯域 である。[0007] The performance evaluation of the infrared detecting element having such a configuration is explained by the specific detection capability D * . Specific detectability D
* Is the S / N ratio when there is an infrared input, and is represented by equation (1). D * = {S × (Ad × Δf) 0.5 } / (N × P) (1) where S: infrared detection signal N: noise signal included in infrared detection signal P: infrared incident energy Ad: infrared Area of detection area Δf: frequency band.
【０００８】また、赤外線検出信号Ｓは、赤外線検出感
度Ｒ×赤外線入射エネルギーＰでも表せるため、（１）
式は次の（２）式のようになる。 Ｄ＊ ＝（Ｒ／Ｎ）×（Ａｄ×Δｆ）０．５ （２）Further, since the infrared detection signal S can be represented by infrared detection sensitivity R × infrared ray incident energy P, (1)
The equation is as shown in the following equation (2). D * = (R / N) × (Ad × Δf) 0.5 (2)
【０００９】赤外線検出感度Ｒは、（３）式で表され
る。 Ｒ＝ｎ×α×Ｒｔｈ （３） 但し、ｎ：サーモパイルの対数 α：ゼーベック係数 Ｒｔｈ：梁およびサーモパイルの並列合成熱抵抗 である。The infrared detection sensitivity R is represented by the following equation (3). R = n × α × Rth (3) where n: logarithm of thermopile α: Seebeck coefficient Rth: parallel combined thermal resistance of beam and thermopile.
【００１０】さらに、梁、サーモパイルの並列合成熱抵
抗Ｒｔｈは、（４）式のようになる。 Ｒｔｈ＝Ｌ／（Ｋ１×Ａ１＋Ｋ２×Ａ２） （４） 但し、Ｋ１：梁の熱伝導率 Ｋ２：サーモパイルの熱伝導率 Ａ１：梁の断面積 Ａ２：サーモパイルの断面積 Ｌ：梁およびサーモパイルの長さ である。Further, the parallel combined thermal resistance Rth of the beam and the thermopile is expressed by the following equation (4). Rth = L / (K1 × A1 + K2 × A2) (4) where K1: thermal conductivity of beam K2: thermal conductivity of thermopile A1: sectional area of beam A2: sectional area of thermopile L: length of beam and thermopile It is.
【００１１】赤外線吸収膜７が、赤外線を受光すれば、
赤外線検知領域２３は周辺のシリコン基板の基枠５に対
して高い温度になる。各サーモパイルはそれぞれ一端が
基枠５、他端が赤外線検出領域２３に連なり、ｐ型ポリ
シリコンサーモパイルとｎ型ポリシリコンサーモパイル
がアルミ配線１０を介して交互に冷点（基枠）と温点
（赤外線検知領域）で直列接続されることにより、ゼー
ベック効果によって起電力が発生する。If the infrared absorbing film 7 receives infrared light,
The temperature of the infrared detection area 23 becomes higher than the temperature of the base frame 5 of the surrounding silicon substrate. One end of each thermopile is connected to the base frame 5 and the other end thereof is connected to the infrared detecting region 23. The p-type polysilicon thermopile and the n-type polysilicon thermopile are alternately arranged with a cold spot (base frame) and a hot spot ( An electromotive force is generated by the Seebeck effect by being connected in series in the infrared detection region).
【００１２】 上述の（１）〜（４）の式で示されるよ
うに、梁２２の熱伝導率が低い、換言すれば熱抵抗が大
きいほどまた、断面積が小さい、換言すれば厚さが薄い
ほど並列合成熱抵抗Ｒｔｈが上がり比検出能Ｄ＊ が向
上することになり、赤外線検出素子の性能は向上する。As indicated by the above equations (1) to (4), the lower the thermal conductivity of the beam 22, that is, the larger the thermal resistance, the smaller the cross-sectional area, in other words, the thickness of the beam 22. As the thickness becomes thinner, the parallel combined thermal resistance Rth rises, and the ratio detection ability D * improves, so that the performance of the infrared detecting element improves.
【００１３】[0013]
【発明が解決しようとする課題】赤外線検出素子は、物
体や人体から発せられる微弱な赤外線を検出するのに用
いられることが多い。その微弱な赤外線を検出するため
には、赤外線検出感度の高感度化が必要である。このた
め、従来の赤外線検出素子にあっては、赤外線検出感度
を上げるために、熱伝導率の低い梁材料、例えば、酸化
膜（ＳｉＯ２ 膜）や窒化膜（ＳｉＮ膜）を用い、更
に、梁の厚さを薄くして梁の熱抵抗を上げていた。しか
しながら、梁の厚さを薄くすると梁の強度が低下してし
まうと言う問題点があった。An infrared detecting element is often used for detecting weak infrared rays emitted from an object or a human body. In order to detect such weak infrared rays, it is necessary to increase the sensitivity of infrared ray detection. For this reason, in the conventional infrared detecting element, a beam material having low thermal conductivity, for example, an oxide film (SiO 2 film) or a nitride film (SiN film) is used in order to increase the infrared detection sensitivity. The thickness of the beam was reduced to increase the thermal resistance of the beam. However, there is a problem in that the strength of the beam is reduced when the thickness of the beam is reduced.
【００１４】本発明は、このような従来の問題点を解決
するためになされたものであり、梁の厚さを薄くするこ
となく、且つ、ＩＣ製造ラインとの整合性の高い製造方
法によって、梁の熱抵抗を大きくした、赤外線検出素子
およびその製造方法を提供することを目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and has been made by a manufacturing method having a high consistency with an IC manufacturing line without reducing the thickness of a beam. An object of the present invention is to provide an infrared detecting element and a method for manufacturing the same, in which the thermal resistance of the beam is increased.
【００１５】[0015]
【課題を解決するための手段】 このため、本発明の赤
外線検出素子は、基枠と、基部に囲まれて配置された赤
外線検知領域と、基枠と赤外線検知領域とを連結する複
数の梁とを有し、その梁が多孔質絶縁膜により形成され
ているものとした。上記の多孔質絶縁膜は多孔質ガラ
ス、とくに発泡したＰＳＧ膜あるいは高ケイ酸ガラスと
するのが好ましい。基枠と赤外線検知領域とを連結する
梁を従来の酸化膜や窒化膜より熱伝導率の低い多孔質絶
縁膜により形成しているので、梁の熱抵抗が大きく向上
する。Therefore, an infrared detecting element according to the present invention includes a base frame, an infrared detecting region arranged to be surrounded by the base, and a plurality of beams connecting the base frame and the infrared detecting region. And the beam is formed of a porous insulating film. The porous insulating film is preferably made of porous glass, particularly a foamed PSG film or high silicate glass. Since the beam connecting the base frame and the infrared detection region is formed of a porous insulating film having lower thermal conductivity than a conventional oxide film or nitride film, the thermal resistance of the beam is greatly improved.
【００１６】また、本発明の赤外線検出素子の製造方法
は、半導体シリコンの基枠と、平面上基枠に囲まれて配
置された赤外線検知領域と、基枠と赤外線検知領域とを
連結する複数の梁と、各梁上に設けられたサーモパイル
とを有する赤外線検出素子の製造方法であって、多角形
状の半導体シリコン基板の上面周辺にそってエッチング
ストッパを形成するとともに、エッチングストッパに囲
まれた内側にエッチング犠牲層を形成する工程Ａと、エ
ッチング犠牲層上の中央部に第１の半導体層を形成する
工程Ｂと、エッチング犠牲層上に、エッチングストッパ
ならびに第１の半導体層との間に間隙をおいて延びると
ともに、一端はエッチングストッパ上に延び、他端は発
泡性材質からなり第１の半導体層に連なる第２の半導体
層を形成する工程Ｃと、第２の半導体層の上面にサーモ
パイルを形成する工程Ｄと、熱処理により第２の半導体
層を発泡させ多孔質絶縁膜とする工程Ｅと、半導体シリ
コン基板のエッチングストッパに囲まれた内側およびエ
ッチング犠牲層をエッチング除去する工程Ｆとを有し
て、第１の半導体層からなる赤外線検知領域を多孔質絶
縁膜からなる梁で支持した赤外線検出素子を得るものと
した。これによれば、ＩＣ製造ラインとの整合性の高い
単なる成膜の工程と熱処理で、強度が大きくかつ熱抵抗
の大きい多孔質絶縁膜の梁が実現され、製造コストも低
く抑えられる。Further, the method of manufacturing an infrared detecting element according to the present invention is directed to a method of manufacturing an infrared detecting element, comprising: a base frame of semiconductor silicon; an infrared detecting region arranged so as to be surrounded by a planar base frame; And a thermopile provided on each of the beams, wherein an etching stopper is formed along the periphery of the upper surface of the polygonal semiconductor silicon substrate and surrounded by the etching stopper. A step A of forming an etching sacrificial layer on the inside, a step B of forming a first semiconductor layer in a central portion on the etching sacrificial layer, and an etching stopper and a first semiconductor layer on the etching sacrificial layer. Forming a second semiconductor layer formed of a foamable material and connected to the first semiconductor layer while extending one end above the etching stopper while extending with a gap therebetween; A step D of forming a thermopile on the upper surface of the second semiconductor layer; a step E of bubbling the second semiconductor layer by heat treatment to form a porous insulating film; And a step F of removing the etching sacrificial layer by etching to obtain an infrared detecting element in which an infrared detecting region made of the first semiconductor layer is supported by a beam made of a porous insulating film. According to this, a beam of a porous insulating film having a large strength and a large thermal resistance can be realized by a simple film forming process and heat treatment having high consistency with an IC manufacturing line, and the manufacturing cost can be kept low.
【００１７】[0017]
【発明の実施の形態】以下、本発明の実施の形態を実施
例により説明する。図１は、本発明の一実施例の赤外線
検出素子を示し、（ａ）は平面図、（ｂ）は（ａ）のＡ
−Ａ断面図、（ｃ）は（ａ）のＢ−Ｂ断面図を示す。こ
の実施例は、多孔質絶縁膜として発泡したＰＳＧ膜を使
用したものである。赤外線検出素子は、全体平面形状が
四角形のシリコン基板１に発泡したＰＳＧ膜により形成
された多孔質絶縁膜梁２を介して赤外線検知領域３を支
持し、多孔質絶縁膜梁２上にサーモパイルを形成して構
成されている。シリコン基板１は、その上面が外周の各
辺に沿ってエッチングストッパ４で幅寸法を画定された
基枠５とされ、基枠５の内側は四角錐状の凹部６となっ
ている。Embodiments of the present invention will be described below with reference to examples. 1A and 1B show an infrared detecting element according to an embodiment of the present invention, wherein FIG. 1A is a plan view, and FIG.
FIG. 2A is a cross-sectional view, and FIG. In this embodiment, a foamed PSG film is used as a porous insulating film. The infrared detecting element supports an infrared detecting area 3 through a porous insulating film beam 2 formed of a PSG film foamed on a silicon substrate 1 having a square planar shape, and a thermopile is placed on the porous insulating film beam 2. It is formed and formed. The upper surface of the silicon substrate 1 is a base frame 5 whose width is defined by an etching stopper 4 along each side of the outer periphery, and the inside of the base frame 5 is a quadrangular pyramid-shaped recess 6.
【００１８】基枠５の各角部近傍から隣接する辺に平行
且つ所定幅の間隙を設けて、図１の（ａ）の平面図上い
ずれも時計方向に多孔質絶縁膜梁２が隣の多孔質絶縁膜
梁２の近傍まで延びている。各多孔質絶縁膜梁２の内側
には、多孔質絶縁膜梁２との間に所定の間隙を設けて赤
外線検知領域３が設けられ、その４つの角部がそれぞれ
各多孔質絶縁膜梁２の先端に接続している。この接続の
ため各多孔質絶縁膜梁２の先端部は、赤外線検出領域３
に向かって直角に曲がっている。A gap having a predetermined width is provided in parallel with the adjacent side from the vicinity of each corner of the base frame 5, and the porous insulating film beam 2 is located clockwise in the plan view of FIG. It extends to the vicinity of the porous insulating film beam 2. An infrared detecting area 3 is provided inside each of the porous insulating film beams 2 with a predetermined gap provided between the porous insulating film beams 2, and four corners of each of the infrared detecting regions 3 are provided. Connected to the tip of For this connection, the tip of each porous insulating film beam 2 is located at the infrared detection region 3.
At a right angle toward.
【００１９】赤外線検知領域３の上には赤外線吸収膜７
が形成されている。また、各多孔質絶縁膜梁２の上に
は、その全長にわたってサーモパイルが設けられてい
る。サーモパイルは、ｐ型ポリシリコンサーモパイル
８、８’とｎ型ポリシリコンサーモパイル９、９’とか
らなり、ｐ型ポリシリコンサーモパイル８、８’が互い
に対向し、ｎ型ポリシリコンサーモパイル９、９’が互
いに対向するように配置されている。そして、各サーモ
パイル間はアルミ配線１０で接続されている。また、赤
外線検知領域３、多孔質絶縁膜梁２および基板１は間隙
１１により分離されている。この赤外線検出素子の構成
は、多孔質絶縁膜梁２と赤外線検知領域３の材質を除い
て、図９に示した従来例と同じである。On the infrared detecting area 3, an infrared absorbing film 7 is provided.
Are formed. A thermopile is provided on each of the porous insulating film beams 2 over its entire length. The thermopile is made up of p-type polysilicon thermopiles 8, 8 'and n-type polysilicon thermopiles 9, 9'. The p-type polysilicon thermopiles 8, 8 'face each other, and the n-type polysilicon thermopiles 9, 9' They are arranged to face each other. The thermopiles are connected by aluminum wiring 10. Further, the infrared detecting region 3, the porous insulating film beam 2, and the substrate 1 are separated by a gap 11. The configuration of this infrared detecting element is the same as that of the conventional example shown in FIG. 9 except for the materials of the porous insulating film beam 2 and the infrared detecting area 3.
【００２０】次に、図２〜図７により上記実施例の赤外
線検出素子の製造方法を説明する。なお、図２〜図７に
おいてそれぞれ（ａ）は平面図、（ｂ）は（ａ）におけ
るＣ−Ｃ断面図である。先ず、第１の工程で、図２に示
すように、シリコン基板１の上面全域にポリシリコンエ
ッチング犠牲層１２をＣＶＤ（Ｃｈｅｍｉｃａｌ Ｖａ
ｐｅｒ Ｄｅｐｏｓｉｔｉｏｎ： 化学的気相成長）に
より形成する。Next, a method of manufacturing the infrared detecting element of the above embodiment will be described with reference to FIGS. 2A to FIG. 7A are plan views, and FIG. 2B is a cross-sectional view taken along line CC in FIG. First, in a first step, as shown in FIG. 2, a polysilicon etching sacrificial layer 12 is formed on the entire upper surface of the silicon substrate 1 by CVD (Chemical Vacuum).
per Deposition (chemical vapor deposition).
【００２１】 次の第２の工程で、図３に示すように、
ポリシリコンエッチング犠牲層１２の外周部にボロンを
注入することにより四角枠形状のポリシリコンエッチン
グストッパ４を形成する。 第３の工程で、ポリシリコ
ンエッチング犠牲層１２およびポリシリコンエッチング
ストッパ４の上面に赤外線検知領域３と多孔質絶縁膜梁
２とになるＰＳＧ膜１４、１５の構造体をＣＶＤにより
形成する。この状態が図４である。In the next second step, as shown in FIG.
By implanting boron into the outer peripheral portion of the polysilicon etching sacrificial layer 12, a rectangular frame-shaped polysilicon etching stopper 4 is formed. In the third step, the structures of the PSG films 14 and 15 which become the infrared detecting region 3 and the porous insulating film beam 2 are formed on the upper surface of the polysilicon etching sacrificial layer 12 and the polysilicon etching stopper 4 by CVD. This state is shown in FIG.
【００２２】そして、第４の工程で、図５に示すよう
に、ＰＳＧ膜１５の上にＣＶＤ等の手法によってｐ型ポ
リシリコンサーモパイル８、８’およびｎ型ポリシリコ
ンサーモパイル９、９’を形成し、アルミ配線１０にて
接続する。In a fourth step, as shown in FIG. 5, p-type polysilicon thermopiles 8, 8 'and n-type polysilicon thermopiles 9, 9' are formed on the PSG film 15 by a technique such as CVD. Then, they are connected by the aluminum wiring 10.
【００２３】このあと、第５の工程で、窒素雰囲気中９
５０°Ｃにて３０分熱処理後、酸素雰囲気中１１５０°
Ｃ、１時間の熱処理を加えて、ＰＳＧ膜１５を発泡さ
せ、図６に示すように、発泡したＰＳＧ膜の多孔質絶縁
膜梁２を形成する。Then, in a fifth step, a 9
After heat treatment at 50 ° C for 30 minutes, 1150 ° C in oxygen atmosphere
C, heat treatment for one hour is applied to foam the PSG film 15, and as shown in FIG. 6, the porous insulating film beam 2 of the foamed PSG film is formed.
【００２４】次に、第６の工程において、図７に示すよ
うに、ＰＳＧ膜１４（赤外線検知領域３）の上に赤外線
吸収膜７の層を蒸着により形成するとともに、強アルカ
リエッチング液によりエッチング犠牲層１２とシリコン
基板１の一部をエッチングする。Next, in a sixth step, as shown in FIG. 7, a layer of an infrared absorbing film 7 is formed on the PSG film 14 (infrared detecting area 3) by vapor deposition, and is etched by a strong alkaline etching solution. The sacrificial layer 12 and a part of the silicon substrate 1 are etched.
【００２５】強アルカリ液によりシリコン基板１表面か
らの異方性エッチングを行うことにより、多孔質絶縁膜
梁２と赤外線検知領域３の層を含む上層とポリシリコン
エッチングストッパ４でカバーされた基枠５の部分を残
して、その内側のシリコン基板１の層がポリシリコンエ
ッチング犠牲層１２と共にエッチングされ、シリコン基
板１に四角錐状の凹部６が形成される。By performing anisotropic etching from the surface of the silicon substrate 1 with a strong alkaline solution, the porous insulating film beam 2, the upper layer including the layer of the infrared detecting region 3 and the base frame covered by the polysilicon etching stopper 4 The layer of the silicon substrate 1 inside the silicon substrate 1 is etched together with the polysilicon etching sacrificial layer 12 except for the portion 5 to form a quadrangular pyramid-shaped recess 6 in the silicon substrate 1.
【００２６】 これにより、間隙１１が多孔質絶縁膜梁
２の根元の縁の周りから延びて、その先端の周りまで形
成される。従って、赤外線検出領域３および多孔質絶縁
膜梁２は、シリコン基板１より分離される。なお、上記
の工程のうち、第１および第２の工程が発明の工程Ａに
該当し、第３の工程が工程Ｂおよび工程Ｃを、第４の工
程が工程Ｄを、第５の工程が工程Ｅを、そして第６の工
程が工程Ｆを構成している。As a result, the gap 11 extends from around the root edge of the porous insulating film beam 2 and is formed up to around its tip. Therefore, the infrared detection region 3 and the porous insulating film beam 2 are separated from the silicon substrate 1. Of the above steps, the first and second steps correspond to the step A of the invention, the third step corresponds to the steps B and C, the fourth step corresponds to the step D, and the fifth step corresponds to the step A. Step E and the sixth step constitute Step F.
【００２７】図８に、ＰＳＧ膜の膨張率と燐濃度との関
係を示す。 ＰＳＧ膜の膨張率は、燐濃度に依存する、
燐濃度５ｍｏｌ％以下では、殆ど膨張は認められない
が、５．５ｍｏｌ％で約１．８倍、６ｍｏｌ％で約３倍
に膨張して、多孔質絶縁膜が形成される。FIG. 8 shows the relationship between the expansion coefficient of the PSG film and the phosphorus concentration. The expansion rate of the PSG film depends on the phosphorus concentration.
At a phosphorus concentration of 5 mol% or less, almost no swelling is observed, but at 5.5 mol%, it expands about 1.8 times, and at 6 mol%, it expands about 3 times to form a porous insulating film.
【００２８】本実施例は以上のように構成され、基枠と
赤外線検知領域とを連結する梁を熱伝導率の低い発泡し
たＰＳＧ膜からなる多孔質絶縁膜により形成したので、
梁の熱抵抗が大きい。したがって、梁の厚さを薄くする
ことなく熱抵抗を増大することができるから、梁の強度
を低下させずに赤外線の検出感度を向上させることがで
きる。また、上記多孔質絶縁膜はＩＣチップ製造で一般
的な成膜の工程と熱処理で実現されるので、ＩＣ製造ラ
インとの整合性が高く、赤外線検出素子の製造コストも
低く抑えられる。In this embodiment, the beam connecting the base frame and the infrared detection region is formed of a porous insulating film made of a foamed PSG film having a low thermal conductivity.
The thermal resistance of the beam is large. Therefore, since the thermal resistance can be increased without reducing the thickness of the beam, the detection sensitivity of infrared rays can be improved without reducing the strength of the beam. In addition, since the porous insulating film is realized by a film forming process and heat treatment generally used in IC chip manufacturing, the compatibility with the IC manufacturing line is high, and the manufacturing cost of the infrared detecting element can be reduced.
【００２９】なお、本実施例の変形例として、多孔質絶
縁膜梁の多孔質ガラスを、発泡したＰＳＧ膜のかわりに
高ケイ酸ガラスを使用して形成することもできる。高ケ
イ酸ガラスを梁に用いる場合には、例えばＮａ２ Ｏ：
５％、Ｂ２ Ｏ３：２０％、ＳｉＯ２ ：７５％の組成の
ホウケイ酸低アルカリガラスを形成し、これに熱処理を
行ってケイ酸とホウ酸ソーダとに分相させる。そして、
濃塩酸で化学的にホウ酸ソーダを溶出させた後、ケイ酸
の骨格からなる成形物を加熱することにより、多孔質の
高ケイ酸ガラスとなる。As a modification of this embodiment, the porous glass of the porous insulating film beam can be formed by using high silicate glass instead of the foamed PSG film. When high silicate glass is used for the beam, for example, Na 2 O:
A low-alkali borosilicate glass having a composition of 5%, B 2 O 3 : 20%, and SiO 2 : 75% is formed, and is subjected to a heat treatment to separate phases into silicic acid and sodium borate. And
After the sodium borate is eluted chemically with concentrated hydrochloric acid, the molded product comprising the skeleton of silicic acid is heated to obtain a porous high silicate glass.
【００３０】なお、上記実施例では、赤外線検知領域と
多孔質絶縁膜梁とになる層を同時に形成するため、双方
とも同じＰＳＧ膜１４、１５の構造体としてＣＶＤによ
り形成したが、これに限定されず、赤外線検知領域には
多孔質となる材質でなく例えば酸化膜（ＳｉＯ２ 膜）
や窒化膜（ＳｉＮ膜）を用いることもできる。In the above embodiment, since the layers to be the infrared detecting region and the porous insulating film beam are simultaneously formed, both are formed by the same structure of the PSG films 14 and 15 by CVD. However, the infrared detecting region is not made of a porous material but is made of, for example, an oxide film (SiO 2 film).
Alternatively, a nitride film (SiN film) can be used.
【００３１】 なお、実施例では、サーモパイル型赤外
線検出素子について説明したが、例えば、抵抗の温度変
化を利用したボロメータ型赤外線検出素子にも適用で
き、比検出能Ｄ＊ の向上が図れる。In the embodiment, the thermopile-type infrared detecting element has been described. However, the present invention can be applied to, for example, a bolometer-type infrared detecting element using a temperature change of a resistor, and the specific detection capability D * can be improved.
【００３２】[0032]
【発明の効果】以上のとおり、本発明の赤外線検出素子
は、基枠と赤外線検知領域とを連結する梁が、例えば発
泡したＰＳＧ膜あるいは高ケイ酸ガラスなど、熱伝導率
の低い多孔質絶縁膜により形成されたものとしたので、
梁の厚さを薄くすることなく熱抵抗を高くでき、強度を
低下させずに赤外線の検出感度を向上させることができ
るという効果を有する。As described above, in the infrared detecting element of the present invention, the beam connecting the base frame and the infrared detecting area is made of a porous insulating material having a low thermal conductivity such as a foamed PSG film or high silicate glass. Since it was assumed that it was formed by the film,
This has the effect that the thermal resistance can be increased without reducing the thickness of the beam, and the detection sensitivity of infrared rays can be improved without reducing the strength.
【００３３】 また本発明の赤外線検出素子の製造方法
は、基枠と赤外線検知領域とを連結する梁の形成にあた
って、発泡性材質の第２の半導体層を形成したあと、熱
処理により第２の半導体層を発泡させ多孔質絶縁膜とす
るものとしたので、強度が大きくかつ熱抵抗の大きい多
孔質絶縁膜の梁が容易に実現される。また、ＩＣ製造ラ
インとの整合性が高いので、製造コストも低く抑えられ
るという効果を有する。Further, in the method for manufacturing an infrared detecting element of the present invention, in forming a beam connecting the base frame and the infrared detecting area, a second semiconductor layer made of a foamable material is formed, and then a second semiconductor is formed by heat treatment. Since the porous insulating film is formed by foaming the layer, a beam of the porous insulating film having high strength and high thermal resistance can be easily realized. In addition, since the compatibility with the IC manufacturing line is high, there is an effect that the manufacturing cost can be reduced.
【図１】本発明の実施例の構成を示す図である。FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.
【図２】実施例の赤外線検出素子の製造過程を示す図で
ある。FIG. 2 is a view showing a manufacturing process of the infrared detecting element of the embodiment.
【図３】実施例の赤外線検出素子の製造過程を示す図で
ある。FIG. 3 is a view showing a manufacturing process of the infrared detecting element of the embodiment.
【図４】実施例の赤外線検出素子の製造過程を示す図で
ある。FIG. 4 is a diagram showing a manufacturing process of the infrared detecting element of the example.
【図５】実施例の赤外線検出素子の製造過程を示す図で
ある。FIG. 5 is a diagram showing a manufacturing process of the infrared detecting element of the example.
【図６】実施例の赤外線検出素子の製造過程を示す図で
ある。FIG. 6 is a diagram showing a manufacturing process of the infrared detecting element of the example.
【図７】実施例の赤外線検出素子の製造過程を示す図で
ある。FIG. 7 is a diagram showing a manufacturing process of the infrared detecting element of the example.
【図８】ＰＳＧ膜の燐濃度と膨張率との関係を示す図で
ある。FIG. 8 is a diagram showing the relationship between the phosphorus concentration and the expansion coefficient of a PSG film.
【図９】従来例を示す図である。FIG. 9 is a diagram showing a conventional example.
１ シリコン基板 ２ 多孔質絶縁膜梁 ３ 赤外線検知領域 ４ ポリシリコンエッチングストッパ ５ 基枠 ６ 四角錐状の凹部 ７ 赤外線吸収膜 ８、８’ ｐ型ポリシリコンサーモパイル ９、９’ ｎ型ポリシリコンサーモパイル １０ アルミ配線 １１ 間隙 １２ ポリシリコンエッチング犠牲層 １４ 赤外線検知領域の構造体 １５ ＰＳＧ膜梁の構造体 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Porous insulating film beam 3 Infrared detection area 4 Polysilicon etching stopper 5 Base frame 6 Square pyramid concave part 7 Infrared absorbing film 8, 8 'P-type polysilicon thermopile 9, 9' N-type polysilicon thermopile 10 Aluminum wiring 11 Gap 12 Polysilicon etching sacrificial layer 14 Structure of infrared detection area 15 Structure of PSG film beam
Claims (5)
外線検知領域と、前記基枠と赤外線検知領域とを連結す
る梁とを有する赤外線検出素子であって、前記梁が多孔
質絶縁膜により形成されていることを特徴とする赤外線
検出素子。1. An infrared detecting element comprising: a base frame; an infrared detection region disposed to be surrounded by the base frame; and a beam connecting the base frame and the infrared detection region. An infrared detecting element formed of a porous insulating film.
ることを特徴とする請求項１記載の赤外線検出素子。2. The infrared detecting element according to claim 1, wherein said porous insulating film is made of porous glass.
であることを特徴とする請求項２記載の赤外線検出素
子。3. The infrared detecting element according to claim 2, wherein said porous glass is a foamed PSG film.
あることを特徴とする請求項２記載の赤外線検出素子。4. The infrared detecting element according to claim 2, wherein the porous glass is a high silicate glass.
に囲まれて配置された赤外線検知領域と、前記基枠と赤
外線検知領域とを連結する複数の梁と、各梁上に設けら
れたサーモパイルとを有する赤外線検出素子の製造方法
であって、多角形状の半導体シリコン基板の上面周辺に
そってエッチングストッパを形成するとともに、該エッ
チングストッパに囲まれた内側にエッチング犠牲層を形
成する工程Ａと、前記エッチング犠牲層上の中央部に第
１の半導体層を形成する工程Ｂと、前記エッチング犠牲
層上に、前記エッチングストッパならびに第１の半導体
層との間に間隙をおいて延びるとともに、一端は前記エ
ッチングストッパ上に延び、他端は発泡性材質からなり
前記第１の半導体層に連なる第２の半導体層を形成する
工程Ｃと、前記第２の半導体層の上面にサーモパイルを
形成する工程Ｄと、熱処理により前記第２の半導体層を
発泡させ多孔質絶縁膜とする工程Ｅと、半導体シリコン
基板の前記エッチングストッパに囲まれた内側およびエ
ッチング犠牲層をエッチング除去する工程Ｆとを有し
て、前記第１の半導体層からなる赤外線検知領域を前記
多孔質絶縁膜からなる梁で支持した赤外線検出素子を得
ることを特徴とする赤外線検出素子の製造方法。5. A base frame made of semiconductor silicon, an infrared detection region arranged on a plane surrounded by the base frame, a plurality of beams connecting the base frame and the infrared detection region, and a plurality of beams provided on each of the beams. A method for manufacturing an infrared detecting element having a thermopile, wherein an etching stopper is formed along the periphery of the upper surface of a polygonal semiconductor silicon substrate, and an etching sacrificial layer is formed inside the etching stopper. A step A, a step B of forming a first semiconductor layer in a central portion on the etching sacrificial layer, and a step extending over the etching sacrificial layer with a gap between the etching stopper and the first semiconductor layer A step C of forming one end of the second semiconductor layer extending over the etching stopper, and the other end of the second semiconductor layer made of a foamable material and connected to the first semiconductor layer; A step D of forming a thermopile on the upper surface of the semiconductor layer, a step E of foaming the second semiconductor layer by heat treatment to form a porous insulating film, and a step of etching the inside of the semiconductor silicon substrate surrounded by the etching stopper and etching sacrifices. A step F of removing the layer by etching to obtain an infrared detecting element in which an infrared detecting region made of the first semiconductor layer is supported by a beam made of the porous insulating film. Production method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14136298A JPH11337403A (en) | 1998-05-22 | 1998-05-22 | Infrared detecting element and its manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14136298A JPH11337403A (en) | 1998-05-22 | 1998-05-22 | Infrared detecting element and its manufacture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11337403A true JPH11337403A (en) | 1999-12-10 |
Family
ID=15290224
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14136298A Pending JPH11337403A (en) | 1998-05-22 | 1998-05-22 | Infrared detecting element and its manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11337403A (en) |
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| JP2007316077A (en) * | 2007-06-08 | 2007-12-06 | Matsushita Electric Works Ltd | Infrared sensor |
| JP2011145296A (en) * | 2010-01-18 | 2011-07-28 | Heimann Sensor Gmbh | Monolithic silicon micromachining type thermopile infrared sensor |
| US8592765B2 (en) | 2010-01-18 | 2013-11-26 | Heimann Sensor Gmbh | Thermopile infrared sensor by monolithic silicon micromachining |
| JP2011215160A (en) * | 2011-08-01 | 2011-10-27 | Panasonic Electric Works Co Ltd | Infrared sensor |
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