JP2006080457A - Imaging device and its manufacturing method - Google Patents

Imaging device and its manufacturing method Download PDF

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JP2006080457A
JP2006080457A JP2004265767A JP2004265767A JP2006080457A JP 2006080457 A JP2006080457 A JP 2006080457A JP 2004265767 A JP2004265767 A JP 2004265767A JP 2004265767 A JP2004265767 A JP 2004265767A JP 2006080457 A JP2006080457 A JP 2006080457A
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Yoshiyuki Kitazawa
良幸 北澤
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Sony Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To suppress a variation in the amount of handling potentials of each photoelectric conversion device and a variation of sensitivity in substrate plane, and prevent color mixture, furthermore, suppress a reduction of numerical aperture of the photoelectric device, and sensitivity deterioration or the like, in rear-surface irradiation type solid state imaging devices. <P>SOLUTION: In the imaging device, a photoelectric conversion device 34 and a plurality of pixels 35 consisting of means Tr for reading a signal charge of this photoelectric conversion device 34 are formed in a semiconductor substrate 32, an opening 52 close to the photoelectric conversion device 34 of each pixel 35 is prepared in the rear side of the semiconductor substrate 32, a reflecting film 45 is formed at least in the inner wall surface of the opening 52, and the rear side surface of the semiconductor substrate 32 is formed as an optical irradiating surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、裏面照射型の固体撮像素子及びその製造方法に関する。   The present invention relates to a back-illuminated solid-state imaging device and a method for manufacturing the same.

従来のＣＭＯＳセンサあるいはＣＣＤセンサ等の固体撮像素子においては、半導体基板に画素となる光電変換部が形成され、光電変換部の信号電荷を読み出す手段等の半導体パターンを形成した基板主面側にカラーフィルタ及びオントップレンズを形成して、基板表面側から光を入射する方式が最も一般的である。しかし、この表面照射型の例えばＣＭＯＳ型固体撮像素子では、半導体ウェハ表面に配線層、遮光層、あるいはゲート電極などが配置されていることから、光電変換部以外のパターン面積によって光電変換部であるフォトダイオードの開口率が低下し、取り扱い電荷量及び感度が低下するという問題があった。また、配線層、遮光層、あるいはゲート電極で乱反射された入射光が隣接する画素に入射することによって混色が発生する。   In a conventional solid-state imaging device such as a CMOS sensor or a CCD sensor, a photoelectric conversion unit serving as a pixel is formed on a semiconductor substrate, and a color is formed on the main surface of the substrate on which a semiconductor pattern such as a means for reading signal charges of the photoelectric conversion unit is formed. The most common method is to form a filter and an on-top lens so that light is incident from the substrate surface side. However, in this surface irradiation type CMOS solid-state imaging device, for example, a wiring layer, a light-shielding layer, or a gate electrode is disposed on the surface of the semiconductor wafer, so that it is a photoelectric conversion unit depending on the pattern area other than the photoelectric conversion unit. There has been a problem that the aperture ratio of the photodiode is lowered, and the amount of charge handled and sensitivity are lowered. In addition, color mixing occurs when incident light irregularly reflected by a wiring layer, a light shielding layer, or a gate electrode enters an adjacent pixel.

近年、これらの問題を解決するために、特許文献１にあるように、画素パターンが形成された主面とは反対側の半導体基板裏面、すなわちシリコンウェハ裏面にカラーフィルタ及びオンチップレンズを形成して、光を裏面から入射する裏面照射型の固体撮像素子が提案されている。   In recent years, in order to solve these problems, as disclosed in Patent Document 1, a color filter and an on-chip lens are formed on the back surface of the semiconductor substrate opposite to the main surface on which the pixel pattern is formed, that is, on the back surface of the silicon wafer. Thus, a back-illuminated solid-state imaging device that makes light incident from the back surface has been proposed.

図１０に、従来のシリコン単結晶基板内部に光電変換部となるフォトダイオードを埋め込んだ裏面照射型のＣＭＯＳ固体撮像素子の一例を示す。同図は要部の断面構造を示す。
この裏面照射型のＣＭＯＳ固体撮像素子１は、第１導電型例えばｐ型のシリコン半導体基板２の表面に各画素を区画するための素子分離領域３を形成し、各区画領域に光電変換部となるフォトダイオード４、フォトダイオードの信号電荷を読み出すための複数のＭＯＳトランジスタＴｒ、例えば読出しトランジスタ、リセットトランジスタ、アンプトランジスタ及び垂直選択トランジスタの４つのＭＯＳトランジスタが形成されて単位画素セル５が形成される。この単位画素セル５が多数個、２次元マトリクッス状に配列される。フォトダイオード４は、各赤色、緑色及び青色に対応したフォトダイオード４Ｒ、４Ｇ及び４Ｂが順次配列されるように形成される。 FIG. 10 shows an example of a back-illuminated CMOS solid-state imaging device in which a photodiode serving as a photoelectric conversion unit is embedded in a conventional silicon single crystal substrate. This figure shows the cross-sectional structure of the main part.
This back-illuminated CMOS solid-state imaging device 1 is formed with an element isolation region 3 for partitioning each pixel on the surface of a first conductivity type, eg, p-type silicon semiconductor substrate 2, and a photoelectric conversion unit and A unit pixel cell 5 is formed by forming a photodiode 4 and a plurality of MOS transistors Tr for reading signal charges of the photodiode, for example, four MOS transistors of a read transistor, a reset transistor, an amplifier transistor, and a vertical selection transistor. . A large number of the unit pixel cells 5 are arranged in a two-dimensional matrix. The photodiode 4 is formed so that the photodiodes 4R, 4G, and 4B corresponding to each of red, green, and blue are sequentially arranged.

フォトダイオード４は、ｐ型半導体基板２の基板表面から所定の深さにわたってイオン注入により形成した第２導電型であるｎ型半導体領域６により形成される。ＭＯＳトランジスタＴｒなどは、ｐ型半導体基板２の表面側に形成したｎ+ ソース／ドレイン領域８とゲート絶縁膜を介して形成したゲート電極９により形成される。このｐ型半導体領域２の表面側には、層間絶縁膜９を介して所要パターンの多層配線１０が形成される。 The photodiode 4 is formed by an n-type semiconductor region 6 of the second conductivity type formed by ion implantation over a predetermined depth from the substrate surface of the p-type semiconductor substrate 2. The MOS transistor Tr or the like is formed by an n + source / drain region 8 formed on the surface side of the p-type semiconductor substrate 2 and a gate electrode 9 formed through a gate insulating film. On the surface side of the p-type semiconductor region 2, a multilayer wiring 10 having a required pattern is formed via an interlayer insulating film 9.

一般的には、これら多層配線層１０が形成された後、表面上に第１のパシベーション膜１２が成膜される。次いで、例えばシリコンウェハによる支持基板２５が基板表面側の第１のパシベーション膜１２上に接着された後、ｐ型半導体基板２の裏面側が１０μｍ以下になるまで研磨除去される。次いで、ｐ型半導体基板２の裏面側にｎ型半導体領域６に接してｐ+ 半導体領域（いわゆるアキュミュレーション層）７が形成される。なお、フォトダイオード４を構成するn型半導体領域６の表面側にもｐ＋半導体領域（いわゆるアキュミュレーション層）２０が形成される。フォトダイオード４は、このｐ＋半導体領域７，２０、ｎ型半導体領域２６及びｐ型半導体基板２によるＨＡＤ（Ｈｏｌｅ Ａｃｃｕｍｕｌａｔｉｏｎ Ｄｉｏｄｅ）構造による埋込みフォトダイオードとして形成される。 Generally, after these multilayer wiring layers 10 are formed, a first passivation film 12 is formed on the surface. Next, for example, a support substrate 25 made of, for example, a silicon wafer is bonded onto the first passivation film 12 on the substrate surface side, and then polished and removed until the back surface side of the p-type semiconductor substrate 2 becomes 10 μm or less. Next, a p + semiconductor region (so-called accumulation layer) 7 is formed on the back side of the p-type semiconductor substrate 2 in contact with the n-type semiconductor region 6. A p + semiconductor region (so-called accumulation layer) 20 is also formed on the surface side of the n-type semiconductor region 6 constituting the photodiode 4. The photodiode 4 is formed as a buried photodiode having a HAD (Hole Accumulation Diode) structure composed of the p + semiconductor regions 7 and 20, the n-type semiconductor region 26 and the p-type semiconductor substrate 2.

基板裏面側の埋込みフォトダイオード４直上に、シリコン酸化膜１３、第２のパシベーション膜（例えばプラズマシリコン窒化膜）１４が順次成膜され、この上に画素間の混色を防止するための遮光膜（例えばＡｌ膜）１５が形成される。さらに、透明平坦化膜１６、カラーフィルタ１７R、１７G、１７Ｂ及びオンチップレンズ１８などの樹脂製薄膜が形成される。符号１９はこの固体撮像素子１を収容したパッケージの上面に配置された赤外線カットフィルタである。   A silicon oxide film 13 and a second passivation film (for example, a plasma silicon nitride film) 14 are sequentially formed immediately above the embedded photodiode 4 on the back side of the substrate, and a light shielding film (for preventing color mixture between pixels) on the silicon oxide film 13 and the second passivation film (for example, plasma silicon nitride film) 14. For example, an Al film) 15 is formed. Further, resin thin films such as the transparent flattening film 16, the color filters 17R, 17G, and 17B and the on-chip lens 18 are formed. Reference numeral 19 denotes an infrared cut filter disposed on the upper surface of the package containing the solid-state imaging device 1.

上述の裏面照射型のＣＭＯＳ固体撮像素子１では、入射光のうち赤外線２１は赤外線カットフィルタ１９によりカットされてフォトダイオード４側への入射が阻止される。赤外線カットフィルタ１９を透過した赤色光線２２、緑色光線２３、青色光線２４は、それぞれ対応する赤色、緑色及び青色に対応するフォトダイオード４Ｒ、４Ｇ及び４Ｂに入射される。遮光膜１５で反射された各色光線２２、２３、２４はフォトダイオード４側に入射されない。   In the backside illumination type CMOS solid-state imaging device 1 described above, the infrared ray 21 of the incident light is cut by the infrared cut filter 19 and is prevented from entering the photodiode 4 side. The red light beam 22, the green light beam 23, and the blue light beam 24 transmitted through the infrared cut filter 19 are incident on the corresponding photodiodes 4R, 4G, and 4B corresponding to red, green, and blue, respectively. Each color light beam 22, 23, 24 reflected by the light shielding film 15 is not incident on the photodiode 4 side.

特開２００３ー３１７８５号公報Japanese Patent Laid-Open No. 2003-31785

ところで、上述の裏面照射型のＣＭＯＳ固体撮像素子１を製造するには、支持基板２５を接着した後、半導体基板２、すなわち数１００μｍ〜７００μｍ厚の単結晶シリコンウェハの裏面を厚さｔ1 が１０μｍ以下になるまで研磨除去することが必須である。しかし、単結晶シリコンウェハの全面を均一な厚さで研磨除去することは難しい。単結晶シリコンウェハの厚さが不均一になると、裏面側の埋込みフォトダイオード４の取り扱い電荷量及び感度がウェハ面内でバラツキを生じるという問題があった。   By the way, in order to manufacture the back-illuminated CMOS solid-state imaging device 1 described above, after the support substrate 25 is bonded, the semiconductor substrate 2, that is, the back surface of a single crystal silicon wafer having a thickness of several hundreds μm to 700 μm is formed with a thickness t1 of 10 μm. It is essential to polish and remove until: However, it is difficult to polish and remove the entire surface of the single crystal silicon wafer with a uniform thickness. When the thickness of the single crystal silicon wafer becomes non-uniform, there is a problem that the charge amount and sensitivity of the embedded photodiode 4 on the back surface side vary within the wafer surface.

また、一般に、長波長の赤色光線２２は単結晶シリコン中の吸収係数が小さいことから、特に混色が発生し易い。すなわち、撮像領域の周辺においてフォトダイオードの水平面に対して斜め方向から入射する赤色光線Ｌ1 は、単結晶シリコン中を透過して隣接画素〔緑色画素、青色画素〕のフォトダイオード４Ｇ，４Ｂ（図示の例ではフォトダイオード４Ｂ）に直接入射して混色の原因となる。この斜め方向からの入射光線Ｌ1 を遮光するためには、画素間に遮光膜１５が必要であるが、単位画素セル５の微細化、集積化を行うために、隣接する画素間のフォトダイオード４を近づけ過ぎた場合、あるいは画素間の遮光膜１５の幅Ｗ1 を小さくし過ぎた場合は、混色を防止することが困難になる。これは、結果的に埋込みフォトダイオード４の面積低下による取り扱い電荷量の低下、あるいは画素開口率の低下に伴う光利用効率の低下を招く。さらに、画素間に配置した遮光膜１５の側面で反射した入射光線Ｌ2 が隣接画素〔青色画素、緑色画素〕のフォトダイオード４Ｂ，４Ｇ（図示の例ではフォトダイオード４Ｇ）へ入射して混色を発生するといった問題もあった。   In general, the long-wavelength red light 22 has a small absorption coefficient in single crystal silicon, so that color mixing is particularly likely to occur. That is, the red light beam L1 incident obliquely with respect to the horizontal plane of the photodiode in the periphery of the imaging region is transmitted through the single crystal silicon, and the photodiodes 4G and 4B (shown in the drawing) of the adjacent pixels (green pixel, blue pixel). In the example, it directly enters the photodiode 4B) and causes color mixing. In order to shield the incident light beam L1 from the oblique direction, a light shielding film 15 is required between the pixels. However, in order to make the unit pixel cell 5 finer and more integrated, the photodiode 4 between adjacent pixels is used. If the distance is too close, or if the width W1 of the light shielding film 15 between the pixels is too small, it is difficult to prevent color mixing. This results in a decrease in the amount of charge handled due to a decrease in the area of the embedded photodiode 4 or a decrease in light utilization efficiency due to a decrease in the pixel aperture ratio. Further, the incident light beam L2 reflected by the side surface of the light shielding film 15 disposed between the pixels enters the photodiodes 4B and 4G (photodiode 4G in the illustrated example) of the adjacent pixels [blue pixel and green pixel] to generate color mixing. There was also the problem of doing.

本発明は、上述の点に鑑み、各光電変換部の取り扱い電荷量及び感度の基板面内でバラツキの抑制及び混色防止、さらに光電変換部の開口率の低下、感度低下等を抑制できる裏面照射型の固体撮像素子を提供するものである。   In view of the above-mentioned points, the present invention provides backside irradiation that can suppress variation and prevention of color mixing within the substrate surface of the handling charge amount and sensitivity of each photoelectric conversion unit, and further suppress a decrease in aperture ratio, a decrease in sensitivity, etc. of the photoelectric conversion unit. A solid-state imaging device of a type is provided.

本発明に係る固体撮像素子は、半導体基板に光電変換部と、光電変換部の信号電荷を読み出す手段からなる複数の画素が形成され、半導体基板の裏面側に各画素の光電変換部に近接した開口部を有して、少なくとも開口部の内壁面に反射膜が形成されてなり、半導体基板の裏面側の面を光照射面としたことを特徴とする。   In the solid-state imaging device according to the present invention, a plurality of pixels including a photoelectric conversion unit and a means for reading out signal charges of the photoelectric conversion unit are formed on a semiconductor substrate, and are adjacent to the photoelectric conversion unit of each pixel on the back surface side of the semiconductor substrate. It has an opening, a reflection film is formed at least on the inner wall surface of the opening, and the surface on the back side of the semiconductor substrate is a light irradiation surface.

開口部の底面から半導体基板の表面までの距離としては、裏面側から照射された可視光を光電変換部へ入射できる距離に設定することが好ましい。
半導体基板の開口部が形成されない領域における裏面から開口部底面に対応する面までの距離としては、可視光を光電変換部まで到達させない距離に設定することが好ましい。
開口部の内壁面及び非開口領域の上面には、反射膜を有することが好ましい。 The distance from the bottom surface of the opening to the surface of the semiconductor substrate is preferably set to a distance at which visible light irradiated from the back side can enter the photoelectric conversion unit.
The distance from the back surface to the surface corresponding to the bottom surface of the opening in the region where the opening of the semiconductor substrate is not formed is preferably set to a distance that does not allow visible light to reach the photoelectric conversion unit.
It is preferable to have a reflective film on the inner wall surface of the opening and the upper surface of the non-opening region.

本発明に係る固体撮像素子の製造方法は、半導体基板の表面側に画素となる光電変換部からの信号電荷を読み出す手段を形成する工程と、半導体基板の裏面側に画素ごとに所定深さの開口部を選択的に形成する工程と、開口部を通じて不純物を導入し半導体基板内に各画素の光電変換部を形成する工程と、開口部の底面を除いて少なくとも開口部内壁面に反射膜を形成する工程を有し、半導体基板の裏面側の面を光照射面として形成することを特徴とする。   The solid-state imaging device manufacturing method according to the present invention includes a step of forming a means for reading out signal charges from a photoelectric conversion unit serving as a pixel on the front surface side of a semiconductor substrate, and a predetermined depth for each pixel on the back surface side of the semiconductor substrate. A step of selectively forming the opening, a step of introducing impurities through the opening to form a photoelectric conversion portion of each pixel in the semiconductor substrate, and forming a reflective film on at least the inner wall surface of the opening except for the bottom surface of the opening And forming a surface on the back surface side of the semiconductor substrate as a light irradiation surface.

上記固体撮像素子の製造方法において、開口部を、裏面側から照射された可視光が開口部底面から光電変換部へ入射できる深さに形成することが好ましい。
上記固体撮像素子の製造方法において、開口部内壁面に反射膜を形成する工程としては、開口部の内面を含む基板裏面の全面に反射膜を形成した後、基板裏面側からエッチバックして、開口部の内壁面に自己整合的に前記反射膜を残すようにすると好ましい。
開口部の形成工程としては、開口部の形成されない領域において入射さる可視光が光電変換部まで到達しない距離を確保するような深さの開口部を形成することが好ましい。
開口部の底面を除いて少なくとも開口部内壁面に反射膜を形成する工程では、開口部の内壁面及び非開口領域の上面には反射膜が残るようにすることが好ましい。 In the method for manufacturing a solid-state imaging device, it is preferable that the opening is formed to a depth at which visible light irradiated from the back side can enter the photoelectric conversion unit from the bottom of the opening.
In the manufacturing method of the solid-state imaging device, as the step of forming the reflective film on the inner wall surface of the opening, the reflective film is formed on the entire surface of the back surface of the substrate including the inner surface of the opening, and then etched back from the back surface side of the substrate. It is preferable to leave the reflective film on the inner wall surface of the part in a self-aligning manner.
As the step of forming the opening, it is preferable to form an opening having a depth so as to secure a distance in which visible light incident in a region where the opening is not formed reaches the photoelectric conversion unit.
In the step of forming the reflective film on at least the inner wall surface of the opening except the bottom surface of the opening, it is preferable that the reflective film remains on the inner wall surface of the opening and the upper surface of the non-opening region.

本発明に係る裏面照射型の固体撮像素子によれば、半導体基板の裏面側に各画素の光電変換部に近接した開口部を有し、少なくとも開口部の内壁面に反射膜が形成されるので、特に撮像領域の周辺画素において斜め方向から入射する光は、開口部の内壁面の反射膜で反射される。このため斜め光は、対応する画素の光電変換部に入射され、隣接する画素への入射が阻止されて混色を回避することができる。この反射膜は、混色防止のための遮光と、入射光を光電変換部へ集光し導く光ガイドとして機能する。   According to the backside illumination type solid-state imaging device according to the present invention, the back surface of the semiconductor substrate has an opening close to the photoelectric conversion portion of each pixel, and a reflection film is formed at least on the inner wall surface of the opening. In particular, light incident from an oblique direction in the peripheral pixels of the imaging region is reflected by the reflective film on the inner wall surface of the opening. For this reason, the oblique light is incident on the photoelectric conversion unit of the corresponding pixel and is prevented from entering the adjacent pixel, thereby preventing color mixing. This reflective film functions as a light guide for preventing color mixing and a light guide for collecting and guiding incident light to the photoelectric conversion unit.

このように開口部の内壁面に形成された反射膜によって、画素間遮光と集光が同時に実現できるので、画素開口率の低下に伴う光利用率の低下、感度の低下、混色等が改善される。本発明では、反射膜が光集光の役割をはたすので、光利用率の向上が図れる。従来では単位画素セルのサイズが微細化するにしたがい画素間の混色防止が困難となるが、本発明では画素開口率を下げることなく微細サイズの画素でも理想的な混色防止を実現できる。   The reflection film formed on the inner wall surface of the opening as described above can simultaneously realize light shielding and condensing between pixels, thereby improving the light utilization rate, sensitivity reduction, color mixing, etc. accompanying the pixel aperture rate reduction. The In the present invention, since the reflection film plays a role of collecting light, the light utilization rate can be improved. Conventionally, it is difficult to prevent color mixture between pixels as the size of the unit pixel cell is miniaturized. However, according to the present invention, ideal color mixture prevention can be realized even for a fine pixel without reducing the pixel aperture ratio.

従来のように半導体基板の厚さを薄く均一に研磨除去する工程を必要としないため、半導体基板の厚さの不均一性を原因とする、従来のような光電変換部での取り扱い電荷量のバラツキ、及び感度のウェハ面内でのバラツキを生じさせることがない。また、半導体基板を薄く研磨除去することがないので、簡便な半導体プロセスにより裏面照射型の固体撮像素子を製造することがきる。   Since there is no need for a process for thinly and uniformly polishing and removing the semiconductor substrate as in the past, the amount of charge handled in the conventional photoelectric conversion unit due to non-uniformity in the thickness of the semiconductor substrate is reduced. Variations and sensitivity variations in the wafer surface do not occur. In addition, since the semiconductor substrate is not thinly removed by polishing, a back-illuminated solid-state imaging device can be manufactured by a simple semiconductor process.

開口部の底面から半導体基板の表面までの距離を、裏面側から照射された可視光を光電変換部へ入射できる距離に設定されるので、各画素での入射光による光電変換を十分に行うことができる。
半導体基板の開口部が形成されない領域における裏面から開口部底面に対応する面までの処理を、可視光が光電変換部まで到達させない距離に設定するので、上記領域の面上に反射膜が形成されていなくても、この領域を入射する可視光の悪影響は生じない。
開口部の内壁面及び非開口領域の上面に反射膜を有するときは、非開口領域から入射される光線が反射膜で反射され、光電変換部への光入射をより確実に阻止することができる。 The distance from the bottom surface of the opening to the surface of the semiconductor substrate is set to a distance at which visible light irradiated from the back side can be incident on the photoelectric conversion unit, so that sufficient photoelectric conversion is performed by incident light at each pixel. Can do.
Since the processing from the back surface to the surface corresponding to the bottom surface of the opening in the region where the opening of the semiconductor substrate is not formed is set to a distance at which visible light does not reach the photoelectric conversion unit, a reflective film is formed on the surface of the region. Even if not, the adverse effect of visible light entering this region does not occur.
When the reflective film is provided on the inner wall surface of the opening and the upper surface of the non-opening region, the light incident from the non-opening region is reflected by the reflective film, and light incidence to the photoelectric conversion unit can be more reliably prevented. .

本発明に係る裏面照射型の固体撮像素子の製造方法によれば、半導体基板の裏面側に画素ごとに所定深さの開口を選択的に形成する工程、開口部の底面を除いて少なくとも開口部内壁面に反射膜を形成する工程を有するので、斜め光による混色を防止し、光利用効率、感度を改善した固体撮像素子を製造することができる。
また、単位画素セルの微細化、高集積化されても混色の生じにくい裏面照射型のＣＭＯＳ固体撮像素子を製造することができる。
半導体基板の厚さを薄く均一に研磨除去する工程を必要としないため、半導体基板の厚が全面均一となり、光電変換部の取り扱い電荷量、ウェハ面内での感度を均一にしたＣＭＯＳ固体撮像素子を製造できる。また、従来の支持基板の貼り合せ工程、半導体基板の厚さを薄くする研磨工程などが省略されるので、製造が容易になる。 According to the manufacturing method of the backside illumination type solid-state imaging device according to the present invention, the step of selectively forming an opening of a predetermined depth for each pixel on the backside of the semiconductor substrate, at least inside the opening except the bottom of the opening Since the method includes the step of forming the reflective film on the wall surface, it is possible to manufacture a solid-state imaging device that prevents color mixing due to oblique light and improves light utilization efficiency and sensitivity.
Further, it is possible to manufacture a back-illuminated CMOS solid-state imaging device in which color mixing is unlikely to occur even when unit pixel cells are miniaturized and highly integrated.
A CMOS solid-state image pickup device in which the thickness of the semiconductor substrate is uniform over the entire surface and the amount of charge handled by the photoelectric conversion unit and the sensitivity within the wafer surface are uniform because the process of thinly and uniformly removing the semiconductor substrate is not required. Can be manufactured. Further, since the conventional support substrate bonding step and polishing step for reducing the thickness of the semiconductor substrate are omitted, the manufacturing becomes easy.

開口部を、裏面側から照射された可視光が開口部底面から光電変換部へ入射できる深さに形成することにより、各画素での入射光による光電変換を十分に行うことができ光電変換部を形成することができる。
開口部内壁に反射膜を形成する工程において、開口部の内面を含む基板裏面の全面に反射膜を形成した後、基板裏面側からエッチバックすることにより、自己整合的に開口部底面の反射膜が除去され、開口部内壁面のみに反射膜を残すことができる。
開口部の形成工程では、開口が形成されない領域において入射される可視光が光電変換部まで到達しない距離を確保するような深さの開口部を形成することにより、反射膜がなくても上記開口が形成されない領域からの光電変換部への光入射を阻止することができる。
反射膜を形成する工程で、開口部の内壁面及び非開口領域の上面に反射膜が残るようにするときには、非開口領域から入射される光線が反射膜で反射され、光電変換部への光入射をより確実に阻止することができる。 By forming the opening at a depth at which visible light irradiated from the back side can enter the photoelectric conversion unit from the bottom of the opening, photoelectric conversion by the incident light at each pixel can be sufficiently performed. Can be formed.
In the step of forming the reflective film on the inner wall of the opening, after forming the reflective film on the entire back surface of the substrate including the inner surface of the opening, the reflective film on the bottom surface of the opening is self-aligned by etching back from the back surface side of the substrate. And the reflective film can be left only on the inner wall surface of the opening.
In the step of forming the opening, the opening is formed even if there is no reflective film by forming an opening having a depth that secures a distance in which visible light incident in a region where the opening is not formed reaches the photoelectric conversion unit. It is possible to prevent light from entering the photoelectric conversion portion from a region where no is formed.
In the step of forming the reflective film, when the reflective film remains on the inner wall surface of the opening and the upper surface of the non-opening region, the light incident from the non-opening region is reflected by the reflective film, and light to the photoelectric conversion unit Incident can be prevented more reliably.

以下、図面を参照して本発明に実施の形態を説明する。   Embodiments of the present invention will be described below with reference to the drawings.

図１に、本発明に係る裏面照射型の固体撮像素子をＣＭＯＳ固体撮像素子に適用した実施の形態を示す。同図は撮像領域の要部の断面構造を示す。
本実施の形態に係る裏面照射型のＣＭＯＳ固体撮像素子３１は、第１導電型例えばｐ型のシリコン半導体基板、いわゆる単結晶シリコンウェハ３２の表面（一方の主面）に各画素を区画するための素子分離領域３３を形成し、各区画領域に光電変換部となるフォトダイオード３４、フォトダイオード３４の信号電荷を読み出すための複数のＭＯＳトランジスタＴｒ、例えば読出しトランジスタ、リセットトランジスタ、アンプトランジスタ及び垂直選択トランジスタの４つのＭＯＳトランジスタが形成されて単位画素セル３５が形成される。この単位画素セル３５が多数個、２次元マトリクッス状に配列される。フォトダイオード３４は、各赤色、緑色及び青色に対応したフォトダイオード３４Ｒ、３４Ｇ及び３４Ｂが順次配列されるように形成される。 FIG. 1 shows an embodiment in which a back-illuminated solid-state imaging device according to the present invention is applied to a CMOS solid-state imaging device. This figure shows a cross-sectional structure of the main part of the imaging region.
The back-illuminated CMOS solid-state imaging device 31 according to the present embodiment partitions each pixel on the surface (one main surface) of a first conductivity type, for example, a p-type silicon semiconductor substrate, that is, a so-called single crystal silicon wafer 32. Device isolation regions 33 and photodiodes 34 serving as photoelectric conversion portions in each partition region, and a plurality of MOS transistors Tr for reading signal charges of the photodiodes 34, for example, read transistors, reset transistors, amplifier transistors, and vertical selections A unit pixel cell 35 is formed by forming four MOS transistors. Many unit pixel cells 35 are arranged in a two-dimensional matrix. The photodiode 34 is formed such that photodiodes 34R, 34G, and 34B corresponding to red, green, and blue are sequentially arranged.

フォトダイオード３４は、ｐ型半導体基板３２の基板表面から所定の深さにわたってイオン注入により形成した第２導電型である例えばｎ型半導体領域３６により形成される。ＭＯＳトランジスタＴｒは、ｐ型半導体基板３２の表面側に形成したｎ+ ソース／ドレイン領域３８とゲート絶縁膜を介して形成したゲート電極３９により形成される。このｐ型半導体領域３２の表面側には、層間絶縁膜３００を介して所要パターンの多層配線４０が形成される。さらに、最上層の層間絶縁膜３００上に例えばプラズマシリコン窒化膜等による第１のパシベーション膜４２が形成される。 The photodiode 34 is formed by, for example, an n-type semiconductor region 36 of the second conductivity type formed by ion implantation from the substrate surface of the p-type semiconductor substrate 32 over a predetermined depth. The MOS transistor Tr is formed by an n + source / drain region 38 formed on the surface side of the p-type semiconductor substrate 32 and a gate electrode 39 formed through a gate insulating film. On the surface side of the p-type semiconductor region 32, a multilayer wiring 40 having a required pattern is formed via an interlayer insulating film 300. Further, a first passivation film 42 made of, for example, a plasma silicon nitride film is formed on the uppermost interlayer insulating film 300.

一方、単結晶シリコンウェハ３２の裏面（他方の主面）には、従来のようにウェハ全体を薄く研磨除去することなく、各画素のフォトダイオード３４のｎ型半導体領域３６が露出するように所要の深さの開口部５２が形成される。この開口部５２は、開口部５２の底面からウェハ表面（一方の主面）までの距離ｍがフォトダイオード３４の深さ、例えば５μｍ〜１０μｍの厚さを残して形成される。また、開口部５２の深さＤは、開口部５２間（いわゆる画素間）の開口部５２が形成されない領域、すなわち非開口領域５３において、可視光のうち最も長波長の赤色光線６２がフォトダイオード３４まで到達しないだけの十分な厚さ（距離）Ｆを確保できる深さに設定される。   On the other hand, it is necessary that the n-type semiconductor region 36 of the photodiode 34 of each pixel is exposed on the back surface (the other main surface) of the single crystal silicon wafer 32 without thinly polishing and removing the entire wafer as in the prior art. An opening 52 having a depth of 5 mm is formed. The opening 52 is formed with a distance m from the bottom surface of the opening 52 to the wafer surface (one main surface) leaving the depth of the photodiode 34, for example, a thickness of 5 μm to 10 μm. Further, the depth D of the opening 52 is such that the red light beam 62 having the longest wavelength among visible light in the region where the openings 52 between the openings 52 (so-called pixels) are not formed, that is, the non-opening region 53. It is set to a depth that can secure a sufficient thickness (distance) F that does not reach 34.

このｎ型半導体領域３６の露出面、開口部５２の内壁面（すなわち内側面）を含む単結晶シリコンウェハ３２の裏面全面に接して第１導電型のアキュミュレーション層、本例ではｐ+ 半導体領域３７が形成される。なお、フォトダイオード４を構成するn型半導体領域６の表面側にも、アキュミュレーション層となるｐ＋半導体領域４６が形成される。フォトダイオード３４は、このｐ+ 半導体領域３７、４６、ｎ型半導体領域３６及びｐ型半導体基板３２によるＨＡＤ構造による埋込みフォトダイオードとして形成される。また、単結晶シリコンウェハ３２の裏面には、開口部５２の底面、側面の内壁面及び非開口領域５３の上面を含む全面に絶縁膜の例えばシリコン酸化膜４３が形成される。さらに、開口部５２の底面を除いて少なくとも内壁面に反射膜４５が形成される。反射膜４５は金属膜が好ましく、例えばＡｌ膜で形成される。そして、開口部５２内に透明絶縁膜５４が埋め込まれる。この透明絶縁膜５４によりウェハ裏面は平坦化される。 An accumulation layer of the first conductivity type in contact with the entire back surface of the single crystal silicon wafer 32 including the exposed surface of the n-type semiconductor region 36 and the inner wall surface (that is, the inner surface) of the opening 52, in this example, a p + semiconductor. Region 37 is formed. A p + semiconductor region 46 serving as an accumulation layer is also formed on the surface side of the n-type semiconductor region 6 constituting the photodiode 4. The photodiode 34 is formed as a buried photodiode having an HAD structure composed of the p + semiconductor regions 37 and 46, the n-type semiconductor region 36 and the p-type semiconductor substrate 32. Further, on the back surface of the single crystal silicon wafer 32, for example, a silicon oxide film 43 of an insulating film is formed on the entire surface including the bottom surface of the opening 52, the inner wall surface of the side surface, and the top surface of the non-opening region 53. Further, the reflective film 45 is formed on at least the inner wall surface except for the bottom surface of the opening 52. The reflective film 45 is preferably a metal film, for example, an Al film. A transparent insulating film 54 is embedded in the opening 52. The back surface of the wafer is flattened by the transparent insulating film 54.

この平坦化されたウェハ裏面上に例えばプラズマシリコン窒化膜等による第２のパシベーション膜４４が形成され、この上にカラーフィルタ４７Ｒ、４７Ｇ、４７Ｂ、オンチップレンズ４８などの樹脂製薄膜が画素ごとに形成される。符号４９は、固体撮像素子３１を収容したパッケ−ジの上面に配置された赤外線カットフィルタである。   A second passivation film 44 made of, for example, a plasma silicon nitride film is formed on the flattened wafer back surface, and resin thin films such as color filters 47R, 47G, 47B and an on-chip lens 48 are formed on the second passivation film 44 for each pixel. It is formed. Reference numeral 49 denotes an infrared cut filter disposed on the upper surface of the package containing the solid-state image pickup device 31.

ＣＭＯＳ固体撮像素子の周辺回路では、ＣＭＯＳトランジスタで構成される。なお、図１では単位画素セルの複数のＭＯＳトランジスタをｎチャネルトランジスタで構成した。   The peripheral circuit of the CMOS solid-state image sensor is composed of CMOS transistors. In FIG. 1, the plurality of MOS transistors of the unit pixel cell are composed of n-channel transistors.

上述の本実施の形態に係る裏面照射型のＣＭＯＳ固体撮像素子３１では、光学レンズ系及び赤外線カットフィルタ４９を通してウェハ裏面を光照射面としてウェハ裏面から光入射される。前述と同様に、入射光のうち赤外線６１は赤外線カットフィルタ４９によりカットされてフォトダイオード３４側への入射が阻止される。赤外線カットフィルタ４９を透過した赤色光線６２、緑色光線６３、青色光線６４は、カラーフィルタを通して、それぞれ対応する赤色、緑色及び青色に対応するフォトダイオード３４Ｒ、３４Ｇ及び３４Ｂに入射される。各色光線については、長波長の赤色光線６２が最も深くフォトダイオード３４Ｒ内に入射され、緑色光線６３が赤色光線６２より浅くフォトダイオード３４Ｇ内に入射され、青色光線６４が最も浅くフォトダイオード３４Ｂ内に入射される。   In the backside illumination type CMOS solid-state imaging device 31 according to the above-described embodiment, light is incident from the backside of the wafer through the optical lens system and the infrared cut filter 49 with the backside of the wafer as a light irradiation surface. In the same manner as described above, the infrared ray 61 of the incident light is cut by the infrared cut filter 49 and is prevented from entering the photodiode 34 side. The red light beam 62, the green light beam 63, and the blue light beam 64 transmitted through the infrared cut filter 49 are incident on the corresponding photodiodes 34R, 34G, and 34B corresponding to red, green, and blue, respectively, through the color filter. For each color ray, the long wavelength red ray 62 is most deeply incident on the photodiode 34R, the green ray 63 is incident on the photodiode 34G shallower than the red ray 62, and the blue ray 64 is shallowest on the photodiode 34B. Incident.

そして、本実施形態の裏面照射型のＣＭＯＳ固体撮像素子３１によれば、単結晶シリコンウェハ３２の裏面側を研磨除去せずに各画素に対応した領域にフォトダイオード３４が臨むような開口部５２を形成し、開口部５２の底面を除いて少なくとも開口部５２の内壁面に反射膜４５を形成している。このような構成により、撮像領域の周辺画素においてフォトダイオード３４に斜め方向から入射する光線（図示の例では長波長の赤色光線）Ｌ3 は、開口部５２の内壁面の反射膜４５で反射されて対応する画素のフォトダイオード３４（図示の例では赤色に対応したフォトダイオード３４Ｒ）に入射され、隣接する画素への入射が阻止されて混色を回避することができる。この反射膜４５は、混色防止のための遮光と、入射光をフォトダイオード３４へ集光し導く光ガイドの役割の機能を合せ持つ。   Then, according to the backside illumination type CMOS solid-state imaging device 31 of the present embodiment, the opening 52 such that the photodiode 34 faces the region corresponding to each pixel without polishing and removing the backside of the single crystal silicon wafer 32. The reflective film 45 is formed on at least the inner wall surface of the opening 52 except for the bottom surface of the opening 52. With such a configuration, light rays (long-wavelength red light rays in the illustrated example) L3 incident on the photodiode 34 from an oblique direction in the peripheral pixels of the imaging region are reflected by the reflective film 45 on the inner wall surface of the opening 52. Incident light is incident on the photodiode 34 of the corresponding pixel (photodiode 34R corresponding to red in the illustrated example), and is prevented from entering adjacent pixels, thereby preventing color mixing. The reflection film 45 has both functions of light shielding for preventing color mixing and a role of a light guide for collecting and guiding incident light to the photodiode 34.

このように開口部５２の内壁面に形成された反射膜４５によって、画素間遮光と集光が同時に実現できるので、画素開口率の低下に伴う光利用率の低下、感度の低下、混色等の問題を生じることがない。本実施形態では、反射膜４５が光集光の役割をはたすので、光利用率の向上が図れる。従来では単位画素セルのサイズが微細化するにしたがい画素間の混色防止が困難となるが、本実施の形態では画素開口率を下げることなく微細サイズの画素でも理想的な混色防止を実現できる。   Since the inter-pixel light shielding and condensing can be realized at the same time by the reflection film 45 formed on the inner wall surface of the opening 52 in this way, a decrease in light utilization rate, a decrease in sensitivity, a color mixture, etc. There is no problem. In the present embodiment, since the reflective film 45 plays a role of collecting light, the light utilization rate can be improved. Conventionally, it is difficult to prevent color mixture between pixels as the size of the unit pixel cell is miniaturized. However, in this embodiment, ideal color mixture prevention can be realized even for a fine pixel without reducing the pixel aperture ratio.

一方、非開口領域５３では、厚さ（距離）Ｆが可視光のうち最も長波長の赤色光線６２がフォトダイオード３４まで到達しないだけの十分な厚さ（距離）を確保しているので、光吸収層としての役割を果している。従って、非開口領域５３に入射された可視光はフォトダイオード３４へ入射されることがない。   On the other hand, the non-opening region 53 has a thickness (distance) F that is sufficient to prevent the red light beam 62 having the longest wavelength of visible light from reaching the photodiode 34. It plays a role as an absorption layer. Accordingly, the visible light incident on the non-opening region 53 is not incident on the photodiode 34.

本実施形態では、従来のように単結晶シリコンウェハ３２の厚さを薄く均一に研磨除去する工程を必要としないため、単結晶シリコンウェハの厚さの不均一性を原因とする、従来のようなフォトダイオード３４の取り扱い電荷量のバラツキ、及び感度のウェハ面内でのバラツキが生じない。また、単結晶シリコンウェハ３２を薄く研磨除去することがないので、簡便な半導体プロセスにより裏面照射型のＣＭＯＳ固体撮像素子を製造することがきる。   In the present embodiment, since the process of thinly and uniformly polishing and removing the thickness of the single crystal silicon wafer 32 as in the conventional method is not required, the thickness of the single crystal silicon wafer is caused to be non-uniform. Therefore, there is no variation in the amount of charge handled by the photodiode 34 and variation in sensitivity within the wafer surface. Further, since the single crystal silicon wafer 32 is not thinly removed by polishing, a back-illuminated CMOS solid-state imaging device can be manufactured by a simple semiconductor process.

次に、図２〜図８を用いて上述の裏面照射型のＣＭＯＳ固体撮像素子３１の製造方法の一例を説明する。
先ず、図２に示すように、第１導電型、例えばｐ型の単結晶シリコンウェハ３２を用意する。このｐ型の単結晶シリコンウェハ３２の表面（一方の主面）に、例えば選択酸化（ＬＯＣＯＳ）層、トレンチ分離等による画素分離のための素子分離領域３３を形成する。また、ウェハ表面に光電変換部の電荷蓄積領域となる第２導電型の例えばｎ+ 半導体領域３６ａを形成し、第２導電型の例えばｎ+ ソース／ドレイン領域３８とゲート絶縁膜とゲート電極３９によるＭＯＳトランジスタＴｒを形成する。ｎ+ 半導体領域３６ａの基板表面側には、アキュミュレーション層となるp+半導体領域４６を形成する。さらに、層間絶縁膜３００を介して接続プラグ４１、多層配線４０を形成し、最上層の層間絶縁膜４０上にだい１のパシベーション膜４２を形成する。 Next, an example of a method for manufacturing the above-described back-illuminated CMOS solid-state imaging device 31 will be described with reference to FIGS.
First, as shown in FIG. 2, a first conductivity type, for example, p-type single crystal silicon wafer 32 is prepared. On the surface (one main surface) of the p-type single crystal silicon wafer 32, for example, a selective oxidation (LOCOS) layer, an element isolation region 33 for pixel isolation by trench isolation or the like is formed. Also, a second conductivity type n + semiconductor region 36a, for example, serving as a charge storage region of the photoelectric conversion unit is formed on the wafer surface, and the second conductivity type n + source / drain region 38, a gate insulating film, and a gate electrode 39 are formed. The MOS transistor Tr is formed. A p + semiconductor region 46 serving as an accumulation layer is formed on the substrate surface side of the n + semiconductor region 36a. Further, the connection plug 41 and the multilayer wiring 40 are formed via the interlayer insulating film 300, and the first passivation film 42 is formed on the uppermost interlayer insulating film 40.

次に、図３に示すように、単結晶シリコンウェハ３２の裏面（他方の主面）に各画素ごとに所要に深さＤの開口部５２を選択エッチングにより形成する。このとき、開口部５２としては、ウェハ表面から開口部５２の底面までの距離ｍが５μｍ〜１０μｍ程度になるように選択エッチングして形成する。従って、隣合う開口部５２間の非開口領域５３の厚さＦは、可視光のうちの最も波長の長い赤色光線が後に形成するフォトダイオードまで到達しないだけの十分な長さを確保することができる。   Next, as shown in FIG. 3, an opening 52 having a required depth D is formed on the back surface (the other main surface) of the single crystal silicon wafer 32 for each pixel by selective etching. At this time, the opening 52 is formed by selective etching so that the distance m from the wafer surface to the bottom surface of the opening 52 is about 5 μm to 10 μm. Therefore, the thickness F of the non-opening region 53 between the adjacent openings 52 can ensure a sufficient length so that the red light having the longest wavelength of visible light does not reach the photodiode to be formed later. it can.

次に、図４に示すように、各開口部５２の底面に臨むウェハ裏面にｎ+ 半導体領域３６ａに接続するようにｎ- 半導体領域３６ｂを例えばイオン注入により形成し、ｎ型半導体領域３６を形成する。さらに、開口部５２の底面に臨むｎ- 半導体領域３６ｂ、開口部５２の内壁面及び非開口領域５３の上面の全表面に不純物を導入して第１導電型であるｐ+ アキュミュレーション層３７を形成する。このようにしてＨＡＤ構造の裏面埋め込み型のフォトダイオード３４〔３４Ｒ，３４Ｇ，３４Ｂ〕を形成する。 Next, as shown in FIG. 4, an n − semiconductor region 36b is formed on the back surface of the wafer facing the bottom surface of each opening 52 so as to be connected to the n + semiconductor region 36a by, for example, ion implantation, and the n-type semiconductor region 36 is formed. Form. Further, an impurity is introduced into the entire surface of the n − semiconductor region 36b facing the bottom surface of the opening 52, the inner wall surface of the opening 52, and the upper surface of the non-opening region 53, and the p + accumulation layer 37 of the first conductivity type. Form. In this way, the backside embedded photodiode 34 [34R, 34G, 34B] having the HAD structure is formed.

次に、図５に示すように、開口部５２の内面を含むウェハ裏面全面に、絶縁膜（例えば熱酸化膜などのシリコン酸化膜）４３を形成し、さらにその上に反射膜４５となる金属膜、例えばＡｌ膜を成膜する。   Next, as shown in FIG. 5, an insulating film (for example, a silicon oxide film such as a thermal oxide film) 43 is formed on the entire back surface of the wafer including the inner surface of the opening 52, and a metal that becomes the reflective film 45 is formed thereon. A film such as an Al film is formed.

次に、図６に示すように、反射膜４５に対してエッチバックを施し、開口部５２の底面の反射膜４５を除去し、開口部５２の内壁面（すなわち内側面）のみに反射膜４５を残す。この反射膜４５は自己整合的に所謂サイドウォールの反射膜として形成される。   Next, as shown in FIG. 6, the reflective film 45 is etched back, the reflective film 45 on the bottom surface of the opening 52 is removed, and the reflective film 45 is applied only to the inner wall surface (that is, the inner side surface) of the opening 52. Leave. The reflective film 45 is formed as a so-called sidewall reflective film in a self-aligning manner.

次に、図７に示すように、開口部５２内に、例えばＳＯＧ（シリコン・オン・グラス）膜などの透明絶縁膜５４を形成し、ウェハ裏面を平坦化する。
その後、図８に示すように、平坦化されたウェハ裏面上に例えばプラズマシリコン窒化膜などの第２のパシベーション膜４４を形成し、さらにカラーフィルタ４７Ｒ、４７Ｇ、４７Ｇ、オンチップレンズ４８を形成して目的の裏面照射型のＣＭＯＳ固体撮像素子３１を得る。 Next, as shown in FIG. 7, a transparent insulating film 54 such as an SOG (silicon on glass) film is formed in the opening 52, and the wafer back surface is flattened.
Thereafter, as shown in FIG. 8, a second passivation film 44 such as a plasma silicon nitride film is formed on the flattened wafer back surface, and color filters 47R, 47G, 47G, and an on-chip lens 48 are formed. Thus, the desired backside illumination type CMOS solid-state imaging device 31 is obtained.

本実施の形態の裏面照射型のＣＭＯＳ固体撮像素子の製造方法によれば、単結晶シリコンウェハ３２の厚さを薄く均一に研磨除去する工程を必要としないため、ウェハ厚が全面均一となり、フォトダイオード３４の取り扱い電荷量、ウェハ面内での感度を均一にしたＣＭＯＳ固体撮像素子を製造できる。また、従来の支持基板の貼り合せ工程、ウェハの厚さを薄くする研磨工程などが省略されるので、製造が容易になる。   According to the backside illumination type CMOS solid-state imaging device manufacturing method of the present embodiment, the thickness of the single crystal silicon wafer 32 is not required to be thinned and uniformly removed. A CMOS solid-state imaging device in which the amount of charge handled by the diode 34 and the sensitivity in the wafer surface are made uniform can be manufactured. Further, since the conventional supporting substrate bonding step and the polishing step for reducing the thickness of the wafer are omitted, the manufacturing becomes easy.

また、単位画素セルの微細化、高集積化されても混色の生じにくい裏面照射型のＣＭＯＳ固体撮像素子を製造することができる。   Further, it is possible to manufacture a back-illuminated CMOS solid-state imaging device in which color mixing is unlikely to occur even when unit pixel cells are miniaturized and highly integrated.

開口部５２の内壁面に反射膜４５を形成する工程において、開口部５２の内面を含むウェハ裏面の全面に反射膜４５を形成した後、ウェハ裏面側からエッチバックすることにより、自己整合的に開口部５２底面の反射膜４５が除去され、開口部５２の内壁面のみに反射膜４５を残すことができる。
開口部５２の形成工程では、非開口領域５３における入射される可視光がフォトダイオード３４まで到達しない距離を確保するような深さＤの開口部を形成することにより、非開口領域５３からのフォトダイオード３４への光入射を阻止することができる。 In the step of forming the reflective film 45 on the inner wall surface of the opening 52, the reflective film 45 is formed on the entire back surface of the wafer including the inner surface of the opening 52, and then etched back from the back surface side of the wafer in a self-aligning manner. The reflective film 45 on the bottom surface of the opening 52 is removed, and the reflective film 45 can be left only on the inner wall surface of the opening 52.
In the step of forming the opening 52, the opening from the non-opening region 53 is formed by forming an opening having a depth D so as to secure a distance where the incident visible light in the non-opening region 53 does not reach the photodiode 34. Light can be prevented from entering the diode 34.

なお、図９Ａ，Ｂに、反射膜４５のエッチバック工程の他の例を示す。この例では、反射膜４５を開口部５２内を含むウェハ全面に形成した後、非開口領域５３の上面に選択的にレジストマスク６７を形成し（図９Ａ参照）、その状態で反射膜４５に対して裏面側からエッチング処理を施す（図９Ｂ参照）。
このエッチバック処理によれば、開口部５２の底面の反射膜４５のみ除去し、他の開口部５２の内壁面及び非開口領域５３の上面には反射膜４５が残る。従って、非開口領域５３に入射される光線はこの反射膜４５で反射され、フォトダイオード側へ入射を確実に阻止することができる。このように、非開口領域上にも反射膜４５を残す構成としたとき、非開口領域５３の厚さＦは前述の条件を満たすことはない。 9A and 9B show another example of the etch back process of the reflective film 45. FIG. In this example, after the reflective film 45 is formed on the entire surface of the wafer including the inside of the opening 52, a resist mask 67 is selectively formed on the upper surface of the non-opening region 53 (see FIG. 9A). On the other hand, an etching process is performed from the back side (see FIG. 9B).
According to this etch back process, only the reflection film 45 on the bottom surface of the opening 52 is removed, and the reflection film 45 remains on the inner wall surface of the other opening 52 and the upper surface of the non-opening region 53. Therefore, the light incident on the non-opening region 53 is reflected by the reflective film 45 and can be reliably prevented from entering the photodiode side. Thus, when it is set as the structure which leaves the reflective film 45 also on a non-opening area | region, the thickness F of the non-opening area | region 53 does not satisfy | fill the above-mentioned conditions.

上例では、本発明を裏面照射型のＣＭＯＳ固体撮像素子に適用したが、その他、図示せざるも裏面照射型のＣＣＤ固体撮像素子にも適用することができる。この場合も、ＣＣＤ固体撮像素子のウェハ裏面側に、上述したように各画素に対応して光電変換部が臨むように開口部を形成し、開口部の内壁面に反射膜を形成するようにして構成することができる。   In the above example, the present invention is applied to a back-illuminated CMOS solid-state image sensor. However, the present invention can also be applied to a back-illuminated CCD solid-state image sensor, which is not shown. Also in this case, an opening is formed on the back side of the wafer of the CCD solid-state imaging device so that the photoelectric conversion unit faces each pixel as described above, and a reflection film is formed on the inner wall surface of the opening. Can be configured.

本発明に係る裏面照射型の固体撮像素子の一実施の形態を示す要部の断面図である。It is sectional drawing of the principal part which shows one Embodiment of the backside illumination type solid-state image sensor concerning this invention. 本発明に係る裏面照射型の固体撮像素子の製造方法の一実施の形態を示す製造工程図（その１）である。It is a manufacturing process figure (the 1) which shows one Embodiment of the manufacturing method of the backside illumination type solid-state image sensor which concerns on this invention. 本発明に係る裏面照射型の固体撮像素子の製造方法の一実施の形態を示す製造工程図（その２）である。It is a manufacturing process figure (the 2) which shows one Embodiment of the manufacturing method of the backside illumination type solid-state image sensor which concerns on this invention. 本発明に係る裏面照射型の固体撮像素子の製造方法の一実施の形態を示す製造工程図（その３）である。It is a manufacturing process figure (the 3) which shows one Embodiment of the manufacturing method of the backside illumination type solid-state image sensor which concerns on this invention. 本発明に係る裏面照射型の固体撮像素子の製造方法の一実施の形態を示す製造工程図（その４）である。It is a manufacturing process figure (the 4) which shows one Embodiment of the manufacturing method of the backside illumination type solid-state image sensor which concerns on this invention. 本発明に係る裏面照射型の固体撮像素子の製造方法の一実施の形態を示す製造工程図（その５）である。It is a manufacturing process figure (the 5) which shows one Embodiment of the manufacturing method of the backside illumination type solid-state image sensor which concerns on this invention. 本発明に係る裏面照射型の固体撮像素子の製造方法の一実施の形態を示す製造工程図（その６）である。It is a manufacturing process figure (the 6) which shows one Embodiment of the manufacturing method of the backside illumination type solid-state image sensor which concerns on this invention. 本発明に係る裏面照射型の固体撮像素子の製造方法の一実施の形態を示す製造工程図（その７）である。It is a manufacturing process figure (the 7) which shows one Embodiment of the manufacturing method of the backside illumination type solid-state image sensor which concerns on this invention. 本発明に係る裏面照射型の固体撮像素子の製造方法の一実施の形態を示す製造工程図（その８）である。It is a manufacturing process figure (the 8) which shows one Embodiment of the manufacturing method of the backside illumination type solid-state image sensor which concerns on this invention. 従来の裏面照射型の固体撮像素子の一例を示す断面図である。It is sectional drawing which shows an example of the conventional backside illumination type solid-state image sensor.

符号の説明Explanation of symbols

３１・・裏面照射型のＣＭＯＳ固体撮像素子、３２・・単結晶シリコンウェハ、３３・・素子分離領域、３４〔３４Ｒ，３４Ｇ，３４Ｂ〕・・フォトダイオード、Ｔｒ・・ＭＯＳトランジスタ、３５・・単位画素セル、３６・・ｎ型半導体領域、３８・・ソース／ドレイン領域、３９・・ゲート電極、４０・・多層配線、４１・・接続プラグ、３７・・ｐ+ アキュミュレーション層、４２・・第１のパシベーション膜、４３・・絶縁膜、４４・・第２のパシベーション膜、４５・・反射膜、４７Ｒ、４７Ｇ、４７Ｇ・・カラーフィルタ、４８・・オンチップレンズ、４９・・赤外線カットフィルタ、５２・・開口部、５３・・非開口領域、６１・・赤外線、６２・・赤色光線、６３・・緑色光線、６４・・青色光線、１００、３００・・層間絶縁膜 31..Back-illuminated CMOS solid-state imaging device, 32..Single crystal silicon wafer, 33..Element isolation region, 34 [34R, 34G, 34B] .. Photodiode, Tr..MOS transistor, 35..Unit Pixel cell, 36..n-type semiconductor region, 38..source / drain region, 39..gate electrode, 40..multilayer wiring, 41..connection plug, 37..p + accumulation layer, 42 .. First passivation film 43.. Insulating film 44.. Second passivation film 45. Reflection film 47 R, 47 G, 47 G Color filter 48 On-chip lens 49 Infrared cut filter , 52 .. Opening, 53 .. Non-opening area, 61 .. Infrared, 62 .. Red light, 63 .. Green light, 64 .. Blue light, 100, 300. Enmaku

Claims (9)

半導体基板に光電変換部と、前記光電変換部の信号電荷を読み出す手段からなる複数の画素が形成され、
前記半導体基板の裏面側に前記各画素の光電変換部に近接した開口部を有して、少なくとも前記開口部の内壁面に反射膜が形成されてなり、
前記半導体基板の裏面側の面を光照射面とした
ことを特徴とする固体撮像素子。 A plurality of pixels including a photoelectric conversion unit and a means for reading signal charges of the photoelectric conversion unit are formed on a semiconductor substrate,
It has an opening close to the photoelectric conversion part of each pixel on the back side of the semiconductor substrate, and a reflection film is formed on at least the inner wall surface of the opening,
A solid-state imaging device, wherein the rear surface of the semiconductor substrate is a light irradiation surface. 前記開口部の底面から前記半導体基板の表面までの距離が、前記裏面側から照射された可視光を前記光電変換部へ入射できる距離に設定されている
ことを特徴とする請求項１記載の固体撮像素子。 2. The solid according to claim 1, wherein a distance from a bottom surface of the opening to a surface of the semiconductor substrate is set to a distance at which visible light irradiated from the back side can be incident on the photoelectric conversion unit. Image sensor. 前記半導体基板の前記開口部が形成されない領域における裏面から開口部底面に対応する面までの距離が、可視光を前記光電変換部まで到達させない距離に設定されている
ことを特徴とする請求項１記載の固体撮像素子。 The distance from the back surface in the area | region where the said opening part of the said semiconductor substrate is not formed to the surface corresponding to an opening part bottom face is set to the distance which does not reach visible light to the said photoelectric conversion part. The solid-state imaging device described. 前記開口部の内壁面及び非開口領域の上面には反射膜を有する
ことを特徴とする請求項１記載の固体撮像素子。 The solid-state imaging device according to claim 1, further comprising a reflective film on an inner wall surface of the opening and an upper surface of the non-opening region. 半導体基板の表面側に画素となる光電変換部からの信号電荷を読み出す手段を形成する工程と、
前記半導体基板の裏面側に前記画素ごとに所定深さの開口部を選択的に形成する工程と、
前記開口部を通じて不純物を導入し前記半導体基板内に各画素の光電変換部を形成する工程と、
前記開口部の底面を除いて少なくとも開口部内壁面に反射膜を形成する工程を有し、
前記半導体基板の裏面側の面を光照射面として形成する
ことを特徴とする固体撮像素子の製造方法。 Forming a means for reading out signal charges from a photoelectric conversion section serving as a pixel on the surface side of the semiconductor substrate;
Selectively forming an opening of a predetermined depth for each pixel on the back side of the semiconductor substrate;
Introducing impurities through the opening to form a photoelectric conversion portion of each pixel in the semiconductor substrate;
Forming a reflective film on at least the inner wall surface of the opening except the bottom surface of the opening;
A method of manufacturing a solid-state imaging device, wherein the surface on the back surface side of the semiconductor substrate is formed as a light irradiation surface. 前記開口部を、前記裏面側から照射された可視光が開口部底面から前記光電変換部へ入射できる深さに形成する
ことを特徴とする請求項５記載の固体撮像素子の製造方法。 The method for manufacturing a solid-state imaging device according to claim 5, wherein the opening is formed to a depth at which visible light irradiated from the back side can enter the photoelectric conversion unit from the bottom of the opening. 前記開口部内壁面に反射膜を形成する工程は、
前記開口部の内面を含む基板裏面の全面に反射膜を形成した後、基板裏面側からエッチバックして、前記開口部の内壁面に自己整合的に前記反射膜を残すようにする
ことを特徴とする請求項５記載の固体撮像素子の製造方法。 The step of forming a reflective film on the inner wall surface of the opening,
A reflective film is formed on the entire back surface of the substrate including the inner surface of the opening, and then etched back from the back surface of the substrate to leave the reflective film on the inner wall surface of the opening in a self-aligning manner. The method for producing a solid-state imaging device according to claim 5. 前記開口部の形成工程は、
前記開口部の形成されない領域において入射さる可視光が光電変換部まで到達しない距離を確保するような深さの開口部を形成する
ことを特徴とする請求項５記載の固体撮像素子の製造方法。 The step of forming the opening includes
The method for manufacturing a solid-state imaging device according to claim 5, wherein an opening having a depth that secures a distance at which visible light incident in a region where the opening is not formed reaches a photoelectric conversion unit is formed. 前記開口部の底面を除いて少なくとも開口部内壁面に反射膜を形成する工程では、
前記開口部の内壁面及び非開口領域の上面には反射膜が残る
ことを特徴とする請求項５記載の固体撮像素子の製造方法。 In the step of forming a reflective film on at least the inner wall surface of the opening except the bottom surface of the opening,
The method for manufacturing a solid-state imaging device according to claim 5, wherein a reflective film remains on an inner wall surface of the opening and an upper surface of the non-opening region.
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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100764061B1 (en) 2006-12-04 2007-10-08 삼성전자주식회사 Image sensor and method of forming the same
JP2008112944A (en) * 2006-10-31 2008-05-15 Sony Corp Solid-state imaging element
JP2008117830A (en) * 2006-11-01 2008-05-22 Sony Corp Solid-state image sensing device, method for manufacturing the same, and image sensing apparatus
WO2008146602A1 (en) * 2007-05-24 2008-12-04 Konica Minolta Holdings, Inc. Radiation detector, method for manufacturing radiation detector, and method for producing supporting substrate
JP2009004550A (en) * 2007-06-21 2009-01-08 Fujifilm Corp Solid-state image pickup element for color picture imaging
JP2009164385A (en) * 2008-01-08 2009-07-23 Fujifilm Corp Imaging device of rear face irradiation type
JP2010539675A (en) * 2006-09-19 2010-12-16 ウードゥヴェ セミコンダクターズ Color image sensor with improved optical crosstalk
JP2011176715A (en) * 2010-02-25 2011-09-08 Nikon Corp Back-illuminated image sensor and imaging apparatus
US8120081B2 (en) 2009-03-23 2012-02-21 Kabushiki Kaisha Toshiba Solid-state imaging device and method for manufacturing same
EP2432019A1 (en) 2010-09-15 2012-03-21 Sony Corporation Imaging device and imaging apparatus
KR101133154B1 (en) 2011-02-03 2012-04-06 디지털옵틱스 코포레이션 이스트 Bsi image sensor package with variable-height silicon for even reception of different wavelengths
WO2012156215A3 (en) * 2011-05-19 2013-03-28 Ams Ag Photodiode and production method
JP2014120610A (en) * 2012-12-17 2014-06-30 Olympus Corp Solid-state image sensor
US8810698B2 (en) 2009-10-07 2014-08-19 Panasonic Intellectual Property Corporation Of America Two sided solid state image sensor and an image capture device
US9041133B2 (en) 2011-02-03 2015-05-26 Nan Chang O-Film Optoelectronics Technology Ltd BSI image sensor package with embedded absorber for even reception of different wavelengths
JP2015179819A (en) * 2014-02-28 2015-10-08 住友電気工業株式会社 Array type light-receiving element
JPWO2018008614A1 (en) * 2016-07-06 2019-04-25 ソニーセミコンダクタソリューションズ株式会社 Image sensor, method of manufacturing image sensor, and electronic device
US11211416B2 (en) 2018-02-09 2021-12-28 Canon Kabushiki Kaisha Photoelectric conversion apparatus having light shielding portions above semiconductor layer on back surface side and equipment

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56138369A (en) * 1980-03-31 1981-10-28 Toshiba Corp Solidstate image sensor
JPS6218075A (en) * 1985-07-17 1987-01-27 Agency Of Ind Science & Technol Photoelectric conversion device
JPS63204666A (en) * 1987-02-16 1988-08-24 フィリップス　エレクトロニクス　ネムローゼ　フェンノートシャップ Radiation sensing semiconductor device
JP2000156523A (en) * 1997-08-29 2000-06-06 Ntt Electornics Corp Semiconductor device
JP2002151668A (en) * 2000-11-10 2002-05-24 Denso Corp Optical integrated circuit and manufacturing method therefor
JP2004031452A (en) * 2002-06-21 2004-01-29 Mitsubishi Electric Corp Rear face incident type imaging device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56138369A (en) * 1980-03-31 1981-10-28 Toshiba Corp Solidstate image sensor
JPS6218075A (en) * 1985-07-17 1987-01-27 Agency Of Ind Science & Technol Photoelectric conversion device
JPS63204666A (en) * 1987-02-16 1988-08-24 フィリップス　エレクトロニクス　ネムローゼ　フェンノートシャップ Radiation sensing semiconductor device
JP2000156523A (en) * 1997-08-29 2000-06-06 Ntt Electornics Corp Semiconductor device
JP2002151668A (en) * 2000-11-10 2002-05-24 Denso Corp Optical integrated circuit and manufacturing method therefor
JP2004031452A (en) * 2002-06-21 2004-01-29 Mitsubishi Electric Corp Rear face incident type imaging device

Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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JP2008112944A (en) * 2006-10-31 2008-05-15 Sony Corp Solid-state imaging element
JP2008117830A (en) * 2006-11-01 2008-05-22 Sony Corp Solid-state image sensing device, method for manufacturing the same, and image sensing apparatus
US7675099B2 (en) 2006-12-04 2010-03-09 Samsung Electronics Co., Ltd. Image sensor and method of forming the same
KR100764061B1 (en) 2006-12-04 2007-10-08 삼성전자주식회사 Image sensor and method of forming the same
WO2008146602A1 (en) * 2007-05-24 2008-12-04 Konica Minolta Holdings, Inc. Radiation detector, method for manufacturing radiation detector, and method for producing supporting substrate
JP4894921B2 (en) * 2007-05-24 2012-03-14 コニカミノルタホールディングス株式会社 Radiation detector, method for manufacturing radiation detector, and method for manufacturing support substrate
JP2009004550A (en) * 2007-06-21 2009-01-08 Fujifilm Corp Solid-state image pickup element for color picture imaging
JP4677425B2 (en) * 2007-06-21 2011-04-27 富士フイルム株式会社 Solid-state image sensor for imaging color images
JP2009164385A (en) * 2008-01-08 2009-07-23 Fujifilm Corp Imaging device of rear face irradiation type
US8120081B2 (en) 2009-03-23 2012-02-21 Kabushiki Kaisha Toshiba Solid-state imaging device and method for manufacturing same
US8810698B2 (en) 2009-10-07 2014-08-19 Panasonic Intellectual Property Corporation Of America Two sided solid state image sensor and an image capture device
US9466633B2 (en) 2010-02-25 2016-10-11 Nikon Corporation Backside illumination image sensor and image-capturing device
US9184197B2 (en) 2010-02-25 2015-11-10 Nikon Corporation Backside illumination image sensor and image-capturing device
US11979672B2 (en) 2010-02-25 2024-05-07 Nikon Corporation Backside illumination image sensor and image-capturing device
US11601624B2 (en) 2010-02-25 2023-03-07 Nikon Corporation Backside illumination image sensor and image-capturing device
US10777595B2 (en) 2010-02-25 2020-09-15 Nikon Corporation Backside illumination image sensor and image-capturing device
US10204949B2 (en) 2010-02-25 2019-02-12 Nikon Corporation Backside illumination image sensor and image-capturing device
US8928795B2 (en) 2010-02-25 2015-01-06 Nikon Corporation Backside illumination image sensor and image-capturing device
US9704902B2 (en) 2010-02-25 2017-07-11 Nikon Corporation Backside illumination image sensor and image-capturing device
JP2011176715A (en) * 2010-02-25 2011-09-08 Nikon Corp Back-illuminated image sensor and imaging apparatus
EP2432019A1 (en) 2010-09-15 2012-03-21 Sony Corporation Imaging device and imaging apparatus
US9041133B2 (en) 2011-02-03 2015-05-26 Nan Chang O-Film Optoelectronics Technology Ltd BSI image sensor package with embedded absorber for even reception of different wavelengths
KR101133154B1 (en) 2011-02-03 2012-04-06 디지털옵틱스 코포레이션 이스트 Bsi image sensor package with variable-height silicon for even reception of different wavelengths
US8937361B2 (en) 2011-02-03 2015-01-20 Digitaloptics Corporation BSI image sensor package with variable-height silicon for even reception of different wavelengths
WO2012106000A1 (en) * 2011-02-03 2012-08-09 Digitaloptics Corporation East Bsi image sensor package with variable-height silicon for even reception of different wavelengths
US9018726B2 (en) 2011-05-19 2015-04-28 Ams Ag Photodiode and production method
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