JP3271222B2 - Solid-state imaging device - Google Patents
Solid-state imaging deviceInfo
- Publication number
- JP3271222B2 JP3271222B2 JP04985994A JP4985994A JP3271222B2 JP 3271222 B2 JP3271222 B2 JP 3271222B2 JP 04985994 A JP04985994 A JP 04985994A JP 4985994 A JP4985994 A JP 4985994A JP 3271222 B2 JP3271222 B2 JP 3271222B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- sensor
- incident
- imaging device
- charge transfer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
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- Transforming Light Signals Into Electric Signals (AREA)
- Solid State Image Pick-Up Elements (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、固体撮像装置に関し、
特に固体撮像装置におけるセンサ部の構造に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device,
It relates specifically to the structure of the sensor unit in the solid-state imaging device.
【０００２】[0002]
【従来の技術】固体撮像装置の一例として、例えばイン
ターライン転送方式のＣＣＤ(ChargeCoupled Device)
エリアセンサの概略構成を図６に示す。同図において、
水平及び垂直方向にて２次元配列されて入射光を光電変
換し、その信号電荷を蓄積する複数個のセンサ部１と、
これらセンサ部１の垂直列毎に配されかつ垂直ブランキ
ング期間の一部にて読出しゲート部２を介して読み出さ
れた信号電荷を垂直方向に転送する垂直電荷転送部３と
によって撮像部４が構成されている。2. Description of the Related Art As an example of a solid-state imaging device, for example, an interline transfer type CCD (Charge Coupled Device) is used.
FIG. 6 shows a schematic configuration of the area sensor. In the figure,
A plurality of sensor units 1 that are two-dimensionally arranged in the horizontal and vertical directions, photoelectrically convert incident light, and accumulate the signal charges;
An image pickup section 4 is provided by a vertical charge transfer section 3 which is arranged for each vertical column of the sensor section 1 and vertically transfers signal charges read through the read gate section 2 during a part of a vertical blanking period. Is configured.
【０００３】この撮像部４において、センサ部１は例え
ばフォトダイオードからなり、垂直電荷転送部３はＣＣ
Ｄによって構成されている。センサ部１から垂直電荷転
送部３に読み出された信号電荷は、水平ブランキング期
間の一部にて１走査線に相当する部分ずつ順に水平転送
部５へ転送される。この１走査線分の信号電荷は、水平
電荷転送部５によって順次水平方向に転送される。In the image pickup section 4, the sensor section 1 is composed of, for example, a photodiode, and the vertical charge transfer section 3 is a CC.
D. The signal charges read from the sensor unit 1 to the vertical charge transfer unit 3 are sequentially transferred to the horizontal transfer unit 5 by a portion corresponding to one scanning line during a part of the horizontal blanking period. The signal charges for one scanning line are sequentially transferred in the horizontal direction by the horizontal charge transfer unit 5.
【０００４】水平電荷転送部５の出力側には、転送され
てきた信号電荷を検出して信号電圧に変換する例えばＦ
ＤＡ(Floating Diffusion Amplifier)からなる電荷検出
部６が配されている。図７に、センサ部１及び垂直電荷
転送部３の断面（図６のＡ‐Ａ′矢視断面）構造の要部
を示す。The output side of the horizontal charge transfer section 5 detects the transferred signal charges and converts them into a signal voltage, for example, F
A charge detection unit 6 including a DA (Floating Diffusion Amplifier) is provided. FIG. 7 shows a main part of a cross-sectional structure (cross-sectional view taken along the line AA ′ in FIG. 6) of the sensor unit 1 and the vertical charge transfer unit 3.
【０００５】上記ＣＣＤエリアセンサにおける垂直電荷
転送部３では、図７に示すように、センサ部１を除く部
分、即ち転送電極７１の外側にアルミニウム等からなる
遮光膜７２を形成することで、信号電荷転送領域７３へ
の外部光の入射を遮断する構造を採っている。In the vertical charge transfer section 3 of the CCD area sensor, as shown in FIG. 7, a light-shielding film 72 made of aluminum or the like is formed on a portion other than the sensor section 1, that is, outside the transfer electrode 71. A structure for blocking the incidence of external light on the charge transfer region 73 is adopted.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、従来の
センサ構造では、図７から明らかなように、センサ部１
の表面が平坦面として形成されているので、センサ部１
に光が斜めに入射した場合、センサ表面で反射した光の
うち遮光膜７２の下端面７２ａに入射する成分があり、
この反射光成分が基板表面と遮光膜７２の下端面７２ａ
又は転送電極７１との間で多重反射を繰り返し、最終的
に信号電荷転送領域７３に飛び込んで光電子を発生し、
スミア成分を増加させるという問題があった。However, in the conventional sensor structure, as is apparent from FIG.
Is formed as a flat surface, the sensor unit 1
When light is incident obliquely, there is a component incident on the lower end surface 72a of the light shielding film 72 in the light reflected on the sensor surface,
This reflected light component is applied to the substrate surface and the lower end surface 72a of the light shielding film 72.
Or, multiple reflection is repeated between the transfer electrode 71 and finally, jump into the signal charge transfer region 73 to generate photoelectrons,
There was a problem of increasing the smear component.
【０００７】本発明は、上記課題に鑑みてなされたもの
であり、その目的とするところは、電荷転送部における
基板表面と遮光膜の下端面又は転送電極との間での多重
反射をなくし、スミアの低減を可能とした固体撮像装置
のセンサ構造を提供することにある。The present invention has been made in view of the above problems, and an object of the present invention is to eliminate multiple reflection between a substrate surface and a lower end surface of a light shielding film or a transfer electrode in a charge transfer section, An object of the present invention is to provide a sensor structure of a solid-state imaging device that can reduce smear.
【０００８】[0008]
【課題を解決するための手段】請求項１記載の固体撮像
装置は、入射光を光電変換してその信号電荷を蓄積する
少なくとも１列分配列された複数個のセンサ部と、この
複数個のセンサ部から読み出された信号電荷を転送する
電荷転送部と、外部光の電荷転送部への入射を遮断する
遮光部とを具備し、複数個のセンサ部の各々の入射面の
少なくとも周縁部が凸凹形状をなすとともに、遮光部に
覆われる位置に配置されてなる構成となっている。According to a first aspect of the present invention, there is provided a solid-state imaging device comprising: a plurality of sensor units arranged in at least one row for photoelectrically converting incident light and accumulating signal charges; A charge transfer unit that transfers a signal charge read from the sensor unit, and blocks external light from entering the charge transfer unit.
A light-shielding portion, and at least the peripheral portion of each of the incident surfaces of the plurality of sensor portions has an uneven shape, and the light-shielding portion
It is configured to be arranged at a position to be covered .
【０００９】請求項２記載の固体撮像装置は、請求項１
記載の固体撮像装置において、複数個のセンサ部の各々
の入射面全面が凸凹形状をなした構成となっている。請
求項３記載の固体撮像装置は、請求項１又は２記載の固
体撮像装置において、凸凹形状の凸部のピッチ及び高さ
が、入射光の波長の１／１０〜１０倍に設定された構成
となっている。According to a second aspect of the present invention, there is provided a solid-state imaging device according to the first aspect.
In the solid-state imaging device described above, the entire incident surface of each of the plurality of sensor units is configured to have an uneven shape. A solid-state imaging device according to a third aspect is the solid-state imaging device according to the first or second aspect, wherein the pitch and the height of the projections are set to 1/10 to 10 times the wavelength of the incident light. It has become.
【００１０】[0010]
【作用】請求項１記載の固体撮像装置において、センサ
部に光が斜めに入射したとき、その入射光は入射面周縁
部の凸凹形状を形成する凸部の側面で反射することで、
電荷転送部側へは入り込まない。したがって、電荷転送
部における基板表面と遮光膜の下端面又は転送電極との
間での多重反射は起こらず、よって電荷転送部の転送領
域に入射しない。また、凸部の側面で反射した光がさら
に他の凸部の側面で反射を繰り返すことで、最終的に基
板側へ透過し、光電変換される。その結果、センサ部の
感度が向上する。In the solid-state imaging device according to the first aspect, when light is obliquely incident on the sensor portion, the incident light is reflected by the side surface of the convex portion forming the irregular shape of the peripheral surface of the incident surface,
It does not enter the charge transfer section. Therefore, multiple reflection does not occur between the substrate surface and the lower end surface of the light-shielding film or the transfer electrode in the charge transfer section, and therefore does not enter the transfer region of the charge transfer section. Further, the light reflected on the side surface of the convex portion is further repeatedly reflected on the side surface of another convex portion, and finally transmitted to the substrate side and photoelectrically converted. As a result, the sensitivity of the sensor unit is improved.
【００１１】請求項２記載の固体撮像装置において、セ
ンサ部にその上方より入射した光は入射面の凸凹面を透
過する際に、その一部が反射する。この反射した光は、
凸部の側面で反射を繰り返すことで、最終的に基板側へ
透過する。すなわち、入射面でのある程度の光の反射は
避けられないが、その反射光も最終的にセンサ部へ取り
込まれる。その結果、センサ部の感度が向上する。請求
項３記載の固体撮像装置では、凸凹形状の凸部のピッチ
及び高さを入射光の波長の１／１０〜１０倍に設定する
ことで、上記作用が有効に発揮される。In the solid-state imaging device according to the second aspect, when light incident on the sensor unit from above is transmitted through the uneven surface of the incident surface, a part of the light is reflected. This reflected light
By repeating the reflection on the side surface of the projection, the light is finally transmitted to the substrate side. That is, although some reflection of light on the incident surface is unavoidable, the reflected light is finally taken into the sensor section. As a result, the sensitivity of the sensor unit is improved. In the solid-state imaging device according to the third aspect, by setting the pitch and the height of the convex portions of the concave and convex shapes to be 1/10 to 10 times the wavelength of the incident light, the above effect is effectively exerted.
【００１２】[0012]
【実施例】以下、本発明の実施例を図面に基づいて詳細
に説明する。図１は、本発明に係るＣＣＤエリアセンサ
におけるセンサ部及び垂直電荷転送部の断面構造図であ
り、図６のＡ‐Ａ′矢視断面を示す。図１において、Ｎ
型シリコン基板１１上にはＰ層からなるオーバーフロー
バリア１２を介してＰウェル１３が積層されている。Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional structural view of a sensor section and a vertical charge transfer section in a CCD area sensor according to the present invention, and shows a cross section taken along the line AA 'in FIG. In FIG. 1, N
A P-well 13 is stacked on the mold silicon substrate 11 via an overflow barrier 12 made of a P-layer.
【００１３】センサ部１は、Ｐウェル１３の表面側に形
成されたＰ＋層からなる正孔蓄積層１４と、その下のＮ
層からなる信号電荷蓄積層１５とからなるＨＡＤ(Hole
Accumulated Diode)構造を採ることで、感度の向上と暗
電流の低減を図っている。この正孔蓄積層１４及び信号
電荷蓄積層１５に隣接してチャネルストップ部１６が形
成されている。垂直電荷転送部３は、基板１１の表面側
に形成された信号電荷転送領域１７と、基板表面上にシ
リコン酸化膜（ＳｉＯ２)よりなる絶縁層１８を介して
形成されたポリシリコンよりなる転送電極１９とによっ
て構成されている。The sensor section 1 has a hole accumulation layer 14 made of a P + layer formed on the surface side of a P well 13 and an N
HAD ( Hole)
The use of an Accumulated Diode structure improves sensitivity and reduces dark current. A channel stop 16 is formed adjacent to the hole accumulation layer 14 and the signal charge accumulation layer 15. The vertical charge transfer section 3 is a transfer made of polysilicon formed on a signal charge transfer region 17 formed on the surface side of the substrate 11 and an insulating layer 18 made of a silicon oxide film (SiO 2 ) on the substrate surface. And the electrode 19.
【００１４】また、センサ部１と垂直電荷転送部３の間
には、センサ部１で光電変換され、信号電荷蓄積層１５
に蓄積された信号電荷を垂直電荷転送部３へ読み出すた
めの読出しゲート部２が設けられている。この読出しゲ
ート部２のゲート電極として、本例では転送電極１９が
兼用されている。そして、センサ部１を除いて読出しゲ
ート部２、垂直電荷転送部３及びチャネルストップ部１
６上には、絶縁層１８を介してアルミニウム等からなる
遮光膜２０が転送電極１９の外側を覆うように設けられ
ている。Between the sensor unit 1 and the vertical charge transfer unit 3, the photoelectric conversion by the sensor unit 1 and the signal charge storage layer 15
A read gate unit 2 for reading out the signal charges stored in the vertical charge transfer unit 3 is provided. In this example, the transfer electrode 19 is also used as a gate electrode of the read gate unit 2. Then, except for the sensor section 1, the readout gate section 2, the vertical charge transfer section 3, and the channel stop section 1
A light-shielding film 20 made of aluminum or the like is provided on 6 via an insulating layer 18 so as to cover the outside of the transfer electrode 19.
【００１５】上記のセンサ構造において、センサ部１の
入射面の少なくとも周縁部、好ましくは入射面全面が凸
凹形状をなしている。この凸凹形状の一例の拡大断面を
図２に示す。同図において、凸凹形状を形成する個々の
凸部２１は円錐形状をなし、そのピッチｐ及び高さｈが
入射光の波長の１／１０〜１０倍程度になるように設定
されている。一例として、入射光の波長を４００ｎｍ〜
７００ｎｍとしたとき、凸部２１のピッチｐ及び高さｈ
は、０．０４μｍ〜７μｍ程度で、しかも画素サイズの
１／１０程度以内に設定される。In the above-described sensor structure, at least the peripheral portion of the incident surface of the sensor section 1, preferably, the entire incident surface has an uneven shape. FIG. 2 shows an enlarged cross section of an example of the uneven shape. In the figure, each convex portion 21 forming a concave and convex shape has a conical shape, and its pitch p and height h are set to be about 1/10 to 10 times the wavelength of the incident light. As an example, the wavelength of the incident light is 400 nm or more.
When the thickness is set to 700 nm, the pitch p and the height h of the projection 21 are set.
Is set to about 0.04 μm to 7 μm, and is set within about 1/10 of the pixel size.
【００１６】上述したように、センサ部１の入射面の少
なくとも周縁部が凸凹形状をなしていることにより、図
３に示すように、センサ部１に光が斜めに入射しても、
円錐状の凸部２１の斜面（側面）で反射する。すると、
その反射光はセンサ部１の上方側ではなく、その下方側
に向けて反射することになる。したがって、センサ部１
の表面での反射光が、垂直電荷転送部３における基板表
面と遮光膜２０の下端面又は転送電極１９との間で多重
反射を繰り返すことはなく、よってその反射光が垂直電
荷転送部３側へ入射することはないので、スミアを大幅
に低減できる。As described above, since at least the peripheral portion of the incident surface of the sensor section 1 has an uneven shape, even if light is obliquely incident on the sensor section 1 as shown in FIG.
The light is reflected on the slope (side surface) of the conical convex portion 21. Then
The reflected light is reflected not on the upper side of the sensor section 1 but on the lower side thereof. Therefore, the sensor unit 1
Does not repeat multiple reflections between the substrate surface in the vertical charge transfer section 3 and the lower end face of the light shielding film 20 or the transfer electrode 19, and therefore the reflected light is not reflected on the vertical charge transfer section 3 side. Since the light does not enter, smear can be significantly reduced.
【００１７】しかも、円錐状の凸部２１の斜面での反射
光は、他の凸部の斜面との間で反射を何回か繰り返すこ
とによって最終的に基板側へ透過し、反射光成分も光電
変換されることになるため、センサ部１の感度を向上で
きる。ところで、センサ部１の表面が平坦な場合、入射
した光の一部は基板側へ透過し、光電変換後信号電荷と
なって蓄積され、有効な信号となる。しかし、シリコン
は屈折率が一般にセンサ部１上に形成される透明膜（カ
ラーフィルタを含む）よりも大きいため、センサ部１の
表面で数１０％は反射されてしまい、光を損失している
のが現状である。Moreover, the reflected light on the slope of the conical convex portion 21 is finally transmitted to the substrate side by repeating reflection several times between the inclined surface of the other convex portion and the reflected light component. Since the photoelectric conversion is performed, the sensitivity of the sensor unit 1 can be improved. Meanwhile, when the surface of the sensor unit 1 is flat, a part of the incident light is transmitted to the substrate side, is accumulated as signal charges after photoelectric conversion, and becomes an effective signal. However, since silicon generally has a higher refractive index than a transparent film (including a color filter) formed on the sensor section 1, several tens of percent of the silicon is reflected on the surface of the sensor section 1 and light is lost. is the current situation.
【００１８】ところが、本実施例においては、センサ部
１の入射面の周縁部のみならず、入射面全面を凸凹形状
としたことにより、センサ部１に上方より入射した光
は、図３に示すように、円錐状の凸部２１の斜面を透過
するとともにその一部が反射することになるが、その反
射光が当該斜面での反射を何回か繰り返すことで最終的
に基板側へ透過する。これにより、従来損失となってい
た反射光成分についても光電変換が行われることになる
ため、センサ部１の感度を向上できる。However, in the present embodiment, not only the periphery of the incident surface of the sensor unit 1 but also the entire incident surface is made uneven, so that light incident on the sensor unit 1 from above is shown in FIG. As described above, the light passes through the slope of the conical convex portion 21 and a part of the light is reflected, but the reflected light is finally transmitted to the substrate side by repeating the reflection on the slope several times. . As a result, the photoelectric conversion is also performed on the reflected light component which has conventionally been lost, so that the sensitivity of the sensor unit 1 can be improved.
【００１９】なお、凸部２１の円錐状の頂角を十分に鋭
角に形成することで、入射光の上方への反射を極めて低
く抑えることが可能となり、センサ部１の感度をより向
上できることになる。また、センサ部１の上方への反射
を低減できることで、セルゴーストなどのフレアの問題
も解消できる。ここに、セルゴーストとは、センサ部１
で反射した光が、ＣＣＤエリアセンサ上にマウントされ
たレンズ等の光学系で多重干渉を起こすことにより、微
小な画素セルが拡大されて映し出される現象を言う。By forming the conical apex angle of the convex portion 21 to be sufficiently acute, it is possible to suppress the upward reflection of the incident light to be extremely low, and to further improve the sensitivity of the sensor portion 1. Become. Further, since the reflection upward from the sensor unit 1 can be reduced, the problem of flare such as a cell ghost can be solved. Here, the cell ghost is the sensor unit 1
Is a phenomenon in which a minute pixel cell is enlarged and projected by causing multiple interference by an optical system such as a lens mounted on a CCD area sensor.
【００２０】これらの作用・効果は、円錐状の凸部２１
のピッチｐ及び高さｈを、先述した如く入射光の波長の
１／１０〜１０倍程度に、しかも画素サイズの１／１０
程度以内に設定することで有効に発揮される。ちなみ
に、円錐状の凸部２１のピッチｐ及び高さｈが小さすぎ
ると、入射光に対して反射の効果はなくなり、逆に大き
すぎると、素子のサイズに比べてセンサ形状が与える他
への悪影響が大きなものとなる。These operations and effects are achieved by the conical projection 21.
Is set to about 1/10 to 10 times the wavelength of the incident light and 1/10 of the pixel size as described above.
Effectively set within this range. Incidentally, if the pitch p and the height h of the conical convex portion 21 are too small, the effect of reflection on incident light is lost, and if too large, on the other hand, the sensor shape gives rise to other effects compared to the element size. The adverse effects are significant.
【００２１】なお、本実施例では、センサ表面の凸凹形
状を形成する凸部２１を円錐状のものとしたが、この形
状に限定されるものではなく、例えば図４に示す如き略
半球状の凸部２１′であっても良く、要は、センサ表面
が平坦面でなく、凸凹であれば、所期の目的を達成する
ことができる。In the present embodiment, the convex portion 21 forming the uneven shape of the sensor surface has a conical shape. However, the present invention is not limited to this shape. For example, a substantially hemispherical shape as shown in FIG. The projection 21 'may be used. In short, the intended purpose can be achieved if the sensor surface is not a flat surface but is uneven.
【００２２】次に、上述したセンサ構造の形成方法につ
いて、図５（ａ）〜（ｄ）の工程図に基づいて説明す
る。先ず、（ａ）工程１では、センサ部１上に転送電極
１８上よりも薄い、例えば５ｎｍ〜３０ｎｍ程度のシリ
コン酸化膜（ＳｉＯ２)を成長させる。次に、ＨＳＧ(He
mispherical Grained：半球状グレイン）ポリシリコン
(Poly-Si)を全面に０．１μｍ程度の微小粒径で成長さ
せる。Next, a method for forming the above-described sensor structure will be described with reference to the process charts of FIGS. First, in step (a), a silicon oxide film (SiO 2 ) having a thickness smaller than that of the transfer electrode 18, for example, about 5 nm to 30 nm is grown on the sensor unit 1. Next, HSG (He
mispherical Grained: polysilicon
(Poly-Si) is grown on the entire surface with a fine particle size of about 0.1 μm.
【００２３】このＨＳＧポリシリコンの形成に際して
は、Ｓｉ２Ｈ６ガスを用いて核付けを行うことによって
低温で核発生させる。そして、これを中心に低温でポリ
シリコンの形成を行う。ＨＳＧの粒密度及び粒径は、Ｓ
ｉ２Ｈ６ガス流量及び基板温度によって決まる。また、
核付け中のＳｉ２Ｈ６分圧は、例えば１０−５〜１０
−４Ｔｏｒｒとする。ＨＳＧポリシリコンの形成方法と
しては、例えば学会誌「応用物理」第６１巻第１１号
（１９９２）１１４７頁〜１１５１頁に開示のものが知
られている。In forming the HSG polysilicon, nucleation is performed at a low temperature by performing nucleation using Si 2 H 6 gas. Then, polysilicon is formed at a low temperature around this. The grain density and grain size of HSG are S
It is determined by the flow rate of the i 2 H 6 gas and the substrate temperature. Also,
The partial pressure of Si 2 H 6 during nucleation is, for example, 10 −5 to 10
-4 Torr. As a method of forming the HSG polysilicon, a method disclosed in, for example, Journal of Applied Physics, Vol. 61, No. 11, (1992), pp. 1147 to 1151, is known.
【００２４】（ｂ）工程２では、ＨＳＧポリシリコンの
隙間から、下のシリコン酸化膜をフッ化水素（ＨＦ）系
溶液でエッチングすることで、センサ表面を局所的に露
出させる。（ｃ）工程３では、シリコンのＲＩＥエッチ
ングにより、センサ表面に微小トレンチを形成する。こ
のとき、不要なポリシリコンは同時に除去される。
（ｄ）工程４では、界面準位安定化のため表面を熱処理
し、ＮＳＧ／ＰＳＧ堆積し、以降通常のＣＣＤプロセス
によって遮光膜１９を形成する。(B) In step 2, the lower silicon oxide film is etched with a hydrogen fluoride (HF) -based solution through a gap between the HSG polysilicon to locally expose the sensor surface. (C) In step 3, minute trenches are formed on the sensor surface by RIE etching of silicon. At this time, unnecessary polysilicon is removed at the same time.
(D) In step 4, the surface is heat-treated to stabilize the interface state, NSG / PSG is deposited, and thereafter, the light shielding film 19 is formed by a normal CCD process.
【００２５】上述したように、センサ表面の凸凹形状を
形成するに際し、センサ部１上に薄いシリコン酸化膜
（ＳｉＯ２)を成長させ、その上にＨＳＧポリシリコン
を形成し、ＨＳＧポリシリコンの隙間から下のシリコン
酸化膜をエッチングしてセンサ表面を局所的に露出させ
ることで、画素サイズが小さいセンサ表面にも容易に凸
凹形状を形成することができる。As described above, when forming the uneven shape of the sensor surface, a thin silicon oxide film (SiO 2 ) is grown on the sensor portion 1, HSG polysilicon is formed thereon, and the gap between the HSG polysilicon is formed. By etching the silicon oxide film below from above to locally expose the sensor surface, an uneven shape can be easily formed even on the sensor surface having a small pixel size.
【００２６】なお、工程３では、局所的に露出したセン
サ表面に微小トレンチを形成するとしたが、これは必須
の要件ではない。ただし、トレンチを形成し、その深さ
を調整することで凸部の高さを任意に設定できる利点が
ある。また、センサ表面の凸凹形状の形成方法として
は、上記の形成方法に限られるものではなく、他にも種
々考えられる。例えば、画素サイズが大きいときは、リ
ソグラフィーとエッチングを使用して凸凹形状を形成す
ることも可能である。In the step 3, the minute trench is formed on the locally exposed sensor surface, but this is not an essential requirement. However, there is an advantage that the height of the convex portion can be arbitrarily set by forming the trench and adjusting the depth thereof. Further, the method of forming the uneven shape of the sensor surface is not limited to the above-described method, and various other methods can be considered. For example, when the pixel size is large, it is possible to form an uneven shape using lithography and etching.
【００２７】また、本発明は、ＣＣＤエリアセンサへの
適用に限定されるものではなく、センサ部が一列粉だけ
配列されたＣＣＤライン（リニア）センサ等、電荷転送
部を有する固体撮像装置全般に適用し得るものである。Further, the present invention is not limited to application to a CCD area sensor, but is generally applied to a solid-state imaging device having a charge transfer section, such as a CCD line (linear) sensor in which a sensor section is arranged only in a single line. Applicable.
【００２８】[0028]
【発明の効果】以上説明したように、請求項１記載の発
明によれば、センサ部の各々の入射面の少なくとも周縁
部を凸凹形状としたことにより、センサ部に斜めに入射
した光が凸凹形状を形成する凸部の側面で反射し、電荷
転送部へは入り込まないため、スミアを大幅に低減でき
ることになる。また、凸部の側面で反射した光がさらに
他の凸部の側面で反射を繰り返すことで、最終的に基板
側へ透過し、光電変換されるため、センサ部の感度を向
上できることにもなる。As described above, according to the first aspect of the present invention, at least the peripheral portion of each incident surface of the sensor section is formed in an uneven shape, so that light obliquely incident on the sensor section is uneven. Since the light is reflected on the side surface of the convex portion forming the shape and does not enter the charge transfer portion, smear can be significantly reduced. Further, the light reflected on the side surface of the convex portion is further reflected on the side surface of another convex portion, and finally transmitted to the substrate side and photoelectrically converted, so that the sensitivity of the sensor portion can be improved. .
【００２９】請求項２記載の発明によれば、センサ部の
各々の入射面の周縁部のみならず、全面を凸凹形状にし
たことにより、センサ部にその上方より入射した光が入
射面の凸凹面を透過する際にその一部が反射しても、こ
の反射した光が凸部の側面で反射を繰り返すことで、最
終的に基板側へ透過し、光電変換されるため、センサ部
の感度を向上できることになる。なお、請求項３記載の
発明によれば、凸凹形状の凸部のピッチ及び高さを入射
光の波長の１／１０〜１０倍に設定することにより、上
記の作用・効果を最大限に発揮できることになる。According to the second aspect of the present invention, not only the peripheral portion of each incident surface of the sensor section but also the entire surface is made uneven, so that light incident on the sensor section from above is uneven. Even if a part of the light is reflected when transmitting through the surface, the reflected light is repeatedly reflected on the side surface of the convex part, and finally transmitted to the substrate side and photoelectrically converted. Can be improved. According to the third aspect of the present invention, by setting the pitch and the height of the convex portions of the irregular shape to 1/10 to 10 times the wavelength of the incident light, the above-described functions and effects are maximized. You can do it.
【図１】本発明の一実施例を示す断面構造図である。FIG. 1 is a sectional structural view showing one embodiment of the present invention.
【図２】センサ表面の拡大断面図である。FIG. 2 is an enlarged sectional view of a sensor surface.
【図３】入射光の振舞いを示す図である。FIG. 3 is a diagram illustrating the behavior of incident light.
【図４】凸部の形状の変形例を示す断面図である。FIG. 4 is a cross-sectional view showing a modification of the shape of the projection.
【図５】本発明によるセンサ構造の形成方法の工程図で
ある。FIG. 5 is a process chart of a method for forming a sensor structure according to the present invention.
【図６】ＣＣＤエリアセンサの概略構成図である。FIG. 6 is a schematic configuration diagram of a CCD area sensor.
【図７】従来例を示す要部の断面図である。FIG. 7 is a sectional view of a main part showing a conventional example.
１…センサ部、３…垂直電荷転送部、５…水平電荷転送
部、１１…Ｎ型シリコン基板、１２…オーバーフローバ
リア、１４…正孔蓄積層、１５…信号電荷蓄積層、１７
…信号電荷転送領域、１９…転送電極、２０…遮光膜、
２１…凸部DESCRIPTION OF SYMBOLS 1 ... Sensor part, 3 ... Vertical charge transfer part, 5 ... Horizontal charge transfer part, 11 ... N-type silicon substrate, 12 ... Overflow barrier, 14 ... Hole accumulation layer, 15 ... Signal charge accumulation layer, 17
... signal charge transfer region, 19 ... transfer electrode, 20 ... light shielding film,
21 ... convex part
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H01L 27/148 H01L 27/14 H01L 27/146 ──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. 7 , DB name) H01L 27/148 H01L 27/14 H01L 27/146
Claims (3)
積する少なくとも１列分配列された複数個のセンサ部
と、 前記複数個のセンサ部から読み出された信号電荷を転送
する電荷転送部と、 外部光の前記電荷転送部への入射を遮断する遮光部と を
具備し、 前記複数個のセンサ部の各々の入射面の少なくとも周縁
部が凸凹形状をなすとともに、前記遮光部に覆われる位
置に配置されてなることを特徴とする固体撮像装置。1. A plurality of sensor units arranged in at least one row for photoelectrically converting incident light and accumulating the signal charges, and charge transfer for transferring signal charges read from the plurality of sensor units. And a light-shielding portion for blocking external light from entering the charge transfer portion. At least a peripheral portion of each of the incident surfaces of the plurality of sensor portions has an uneven shape and is covered by the light-shielding portion. Place
A solid-state imaging device characterized by being arranged in a device.
面が凸凹形状をなしていることを特徴とする請求項１記
載の固体撮像装置。2. The solid-state imaging device according to claim 1, wherein the entire incident surface of each of the plurality of sensor units has an uneven shape.
は、入射光の波長の１／１０〜１０倍に設定されている
ことを特徴とする請求項１又は２記載の固体撮像装置。3. The solid-state imaging device according to claim 1, wherein a pitch and a height of the projections are set to 1/10 to 10 times the wavelength of incident light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04985994A JP3271222B2 (en) | 1994-02-22 | 1994-02-22 | Solid-state imaging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04985994A JP3271222B2 (en) | 1994-02-22 | 1994-02-22 | Solid-state imaging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07235658A JPH07235658A (en) | 1995-09-05 |
| JP3271222B2 true JP3271222B2 (en) | 2002-04-02 |
Family
ID=12842787
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04985994A Expired - Fee Related JP3271222B2 (en) | 1994-02-22 | 1994-02-22 | Solid-state imaging device |
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| Country | Link |
|---|---|
| JP (1) | JP3271222B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7781485B2 (en) | 2004-11-09 | 2010-08-24 | Kyowa Hakko Kirin Co., Ltd. | Hsp90 family protein inhibitors |
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-
1994
- 1994-02-22 JP JP04985994A patent/JP3271222B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7781485B2 (en) | 2004-11-09 | 2010-08-24 | Kyowa Hakko Kirin Co., Ltd. | Hsp90 family protein inhibitors |
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| Publication number | Publication date |
|---|---|
| JPH07235658A (en) | 1995-09-05 |
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