JP2009170539A - Back-illuminated image sensor and method of driving the same - Google Patents

Back-illuminated image sensor and method of driving the same Download PDF

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JP2009170539A
JP2009170539A JP2008004748A JP2008004748A JP2009170539A JP 2009170539 A JP2009170539 A JP 2009170539A JP 2008004748 A JP2008004748 A JP 2008004748A JP 2008004748 A JP2008004748 A JP 2008004748A JP 2009170539 A JP2009170539 A JP 2009170539A
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Ryoichi Honma
亮一 本間
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Fujifilm Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a back-illuminated image sensor that improves efficiency for reading out signal charges while preventing the occurrence of crosstalk, and to provide a method of driving the same. <P>SOLUTION: The back-illuminated image sensor 10 is configured to take an image by emitting light from the backside of a semiconductor substrate 1 and reading out charges, occurring inside the semiconductor substrate 1 corresponding to incident light, from the surface side of the semiconductor substrate 1. The back-illuminated image sensor includes an impurity diffused layer PD provided on the semiconductor substrate 1 so as to generate signal charges by photoelectrically converting incident light, a circuit board 2 formed on the surface side of the semiconductor substrate 1, a charge transfer region 18 provided on the surface side of the semiconductor substrate 1 so as to transfer the signal charges, and a charge collecting electrode 12 for collecting the signal charges generated by the impurity diffused layer PD to the surface side of the semiconductor substrate 1 while applying a voltage to the circuit board 2 during imaging. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、半導体基板の裏側面から光を照射し、入射光に応じて半導体基板内で発生した電荷を、半導体基板の表面側から読み出して撮像を行う裏面照射型撮像素子及び裏面照射型撮像素子の駆動方法に関する。   The present invention relates to a backside-illuminated imaging device and a backside-illuminated imaging in which light is irradiated from the back side surface of a semiconductor substrate, and charges generated in the semiconductor substrate are read out from the surface side of the semiconductor substrate in response to incident light. The present invention relates to an element driving method.

半導体基板の裏面側から光を照射し、この光に応じて半導体基板内で発生した電荷を、半導体基板の表面側に形成された電荷蓄積領域に蓄積し、ここに蓄積された電荷に応じた信号を、読み出し回路等によって外部に出力して撮像を行う裏面照射型撮像素子が提案されている。   Light is irradiated from the back side of the semiconductor substrate, and charges generated in the semiconductor substrate in response to the light are accumulated in a charge accumulation region formed on the surface side of the semiconductor substrate, and according to the accumulated charges There has been proposed a back-illuminated imaging device that outputs a signal to the outside by a readout circuit or the like and performs imaging.

下記特許文献1に示す裏面照射型撮像素子は、P型のエピタキシャル層を有する半導体基板に配線層を設け、裏面に受光面を有し、受光面から入射した光の電子をフォトダイオードによって誘導し、エピタキシャル層の深さ方向に電場を形成する構成である。   A back-illuminated image sensor shown in Patent Document 1 below has a wiring layer on a semiconductor substrate having a P-type epitaxial layer, a light-receiving surface on the back surface, and guides light electrons incident from the light-receiving surface by a photodiode. The electric field is formed in the depth direction of the epitaxial layer.

特開2003−338615号公報JP 2003-338615 A

ところで、上記の構成の裏面照射型撮像素子は、裏面の近くで光電変換された電子が、光電変換された領域の下に設けられた電荷転送領域ではなく、隣り合う画素の電荷転送領域へ移動し、転送されてしまう、所謂、クロストークが発生し、画質が低下する要因となることが懸念される。   By the way, in the backside-illuminated imaging device having the above configuration, electrons photoelectrically converted near the backside move to a charge transfer region of an adjacent pixel instead of a charge transfer region provided under the photoelectrically converted region. However, there is a concern that so-called crosstalk, which is transferred, may occur, which may be a cause of deterioration in image quality.

本発明は、上記事情に鑑みてなされたもので、その目的は、クロストークの発生を抑制することができるとともに、信号電荷の読み出しの効率を向上することができる裏面照射型撮像素子及び裏面照射型撮像素子の駆動方法を提供することにある。   The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a backside-illuminated imaging device and backside illumination that can suppress the occurrence of crosstalk and improve the efficiency of reading signal charges. Another object of the present invention is to provide a method for driving a type imaging device.

本発明の上記目的は、下記構成によって達成される。
(1)半導体基板の裏面側から光を照射し、入射光に応じて前記半導体基板内で発生した電荷を、前記半導体基板の表面側から読み出して撮像を行う裏面照射型撮像素子であって、
前記半導体基板に設けられ、入射光を光電変換することで信号電荷を生成する不純物拡散層と、
前記半導体基板の表面側に形成された回路基板と、
前記半導体基板の表面側に設けられ、信号電荷を転送する電荷転送領域とを備え、
前記回路基板に、撮像時に電圧が印加されることで、前記不純物拡散層で生成される信号電荷を前記半導体基板の表面側に捕集する電荷捕集電極を備えていることを特徴とする裏面照射型撮像素子。
(2)前記回路基板の裏面側に、信号電荷を転送する駆動電圧が印加される電荷転送電極が設けられ、電荷転送時に、前記電荷捕集電極と前記電荷転送電極にそれぞれ電圧を印加し、信号電荷を前記電荷転送領域に誘導する電圧供給部が設けられていることを特徴とする上記(1)に記載の裏面照射型撮像素子。
(3)半導体基板の裏面側から光を照射し、入射光に応じて前記半導体基板内で発生した電荷を、前記半導体基板の表面側から読み出して撮像を行う裏面照射型撮像素子の駆動方法であって、
前記裏面照射型撮像素子に、入射光を光電変換することで信号電荷を生成するため前記半導体基板に設けられた不純物拡散層と、前記半導体基板の表面側に形成された回路基板と、前記半導体基板の表面側に設けられ、信号電荷を転送する電荷転送領域とが備えられ、
撮像時に、前記回路基板に設けられた電荷捕集電極に電圧を印加することで、前記不純物拡散層で生成される信号電荷を前記半導体基板の表面側に捕集することを特徴とする裏面照射型撮像素子の駆動方法。
(4)前記回路基板の裏面側に、信号電荷を転送する駆動電圧が印加される電荷転送電極が設けられ、電荷転送時に、前記電荷捕集電極と前記電荷転送電極にそれぞれ電圧を印加することで、信号電荷を前記電荷転送領域に誘導することを特徴とする上記(3)に記載の裏面照射型撮像素子の駆動方法。
The above object of the present invention is achieved by the following configurations.
(1) A backside illuminating type imaging device that irradiates light from the back side of a semiconductor substrate, reads out charges generated in the semiconductor substrate in response to incident light from the front side of the semiconductor substrate, and performs imaging.
An impurity diffusion layer that is provided on the semiconductor substrate and generates signal charges by photoelectrically converting incident light; and
A circuit board formed on the surface side of the semiconductor substrate;
A charge transfer region provided on the surface side of the semiconductor substrate and transferring a signal charge;
A back surface comprising a charge collection electrode that collects a signal charge generated in the impurity diffusion layer on the front side of the semiconductor substrate when a voltage is applied to the circuit board during imaging. Irradiation type image sensor.
(2) A charge transfer electrode to which a driving voltage for transferring a signal charge is applied is provided on the back side of the circuit board, and a voltage is applied to each of the charge collection electrode and the charge transfer electrode during charge transfer, The backside illumination type image pickup device according to (1), wherein a voltage supply unit for inducing signal charges to the charge transfer region is provided.
(3) A method of driving a backside illuminating type imaging device that irradiates light from the back side of the semiconductor substrate and reads out the charge generated in the semiconductor substrate in response to incident light from the front side of the semiconductor substrate to perform imaging. There,
Impurity diffusion layers provided on the semiconductor substrate for generating signal charges by photoelectrically converting incident light into the back-illuminated image sensor, a circuit substrate formed on the front side of the semiconductor substrate, and the semiconductor A charge transfer region provided on the surface side of the substrate and transferring a signal charge,
Backside illumination characterized by collecting signal charges generated by the impurity diffusion layer on the front side of the semiconductor substrate by applying a voltage to a charge collection electrode provided on the circuit board during imaging Type image sensor driving method.
(4) A charge transfer electrode to which a driving voltage for transferring a signal charge is applied is provided on the back side of the circuit board, and a voltage is applied to each of the charge collection electrode and the charge transfer electrode during charge transfer. Then, the signal charge is guided to the charge transfer region, and the driving method of the backside illuminating type image pickup device according to (3) above.

本発明にかかる裏面照射型撮像素子は、半導体基板に積層された回路基板に電荷捕集電極が設けられ、電圧を印加することができる構成であるため、撮像時に電圧を印加することで不純物拡散層で光電変換により生成された信号電荷を半導体基板の表面側に捕集することができる。すると、信号電荷が、電荷捕集電極へ誘導されるため、隣り合う他の画素の電荷転送領域へ誘導されてしまうことを抑制される。   The back-illuminated imaging device according to the present invention has a structure in which a charge collection electrode is provided on a circuit board laminated on a semiconductor substrate and voltage can be applied. Therefore, impurity diffusion is achieved by applying voltage during imaging. The signal charge generated by photoelectric conversion in the layer can be collected on the surface side of the semiconductor substrate. Then, since the signal charge is induced to the charge collection electrode, it is suppressed that the signal charge is induced to the charge transfer region of another adjacent pixel.

また、本発明にかかる裏面照射型撮像素子は、電荷転送時に、電荷捕集電極と電荷転送電極にそれぞれ電圧を印加し、信号電荷を電荷転送領域に誘導する電圧供給部が設けられている構成とすることが好ましい。こうすれば、信号読み出し時に、電荷捕集電極と電荷転送電極とのそれぞれに所定の電圧を印加することで、電荷捕集電極と電荷転送電極との間の電位ポテンシャルを制御することができ、従来のように電荷転送電極にのみ電圧を印加する構成に比べて、信号電荷の読み出しを円滑に行うことができ、信号読み出しの効率を向上できる。また、電荷捕集電極に印加する電圧を電荷転送電極に印加する電圧に対して十分に低くすることで、電荷転送電極に印加する最大電圧の値をできるだけ小さくすることができ、この結果、電荷転送電極を駆動するための電源電圧を低くすることができる。   The backside illumination type image pickup device according to the present invention includes a voltage supply unit that applies a voltage to each of the charge collection electrode and the charge transfer electrode during charge transfer and induces signal charges to the charge transfer region. It is preferable that In this way, the potential potential between the charge collection electrode and the charge transfer electrode can be controlled by applying a predetermined voltage to each of the charge collection electrode and the charge transfer electrode during signal readout, Compared to the conventional configuration in which a voltage is applied only to the charge transfer electrode, signal charges can be read more smoothly, and the efficiency of signal reading can be improved. Also, by making the voltage applied to the charge collection electrode sufficiently lower than the voltage applied to the charge transfer electrode, the value of the maximum voltage applied to the charge transfer electrode can be made as small as possible. The power supply voltage for driving the transfer electrode can be lowered.

本発明によれば、クロストークの発生を抑制することができるとともに、信号電荷の読み出し効率を向上することができる裏面照射型撮像素子及び裏面照射型撮像素子の駆動方法を提供できる。   ADVANTAGE OF THE INVENTION According to this invention, while being able to suppress generation | occurrence | production of crosstalk, the drive method of the back irradiation type image pick-up element which can improve the reading efficiency of a signal charge and a back surface irradiation type image pick-up element can be provided.

以下、本発明の実施形態を図面に基づいて詳しく説明する。
図1は、本発明にかかる裏面照射型撮像素子の一実施形態の構成を示す断面図である。
裏面照射型撮像素子10は、裏面側から入射光が入射し、入射光に応じて光電変換を行い、信号電荷を生成する光学変換層が形成された半導体基板1と、半導体基板1で生成された信号電荷を転送するための駆動電圧などを印加するための回路が形成された回路基板2とから構成されている。回路基板2は、半導体基板1の表面側、つまり、入射光が入射する半導体基板1の裏面側に対して反対側に絶縁層を介して設けられている。
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a configuration of an embodiment of a backside illumination type imaging device according to the present invention.
The back-illuminated imaging element 10 is generated by a semiconductor substrate 1 on which incident light is incident from the back surface side, photoelectric conversion is performed according to the incident light, and an optical conversion layer that generates signal charges is formed, and the semiconductor substrate 1. And a circuit board 2 on which a circuit for applying a driving voltage for transferring the signal charge is formed. The circuit board 2 is provided via an insulating layer on the front surface side of the semiconductor substrate 1, that is, on the opposite side to the back surface side of the semiconductor substrate 1 on which incident light is incident.

裏面照射型撮像素子10は、半導体基板1の一方の面側から照射される入射光を光電変換することで信号電荷を発生させ、該半導体基板1の他方の面側から信号電荷を読み出して撮像を行う構成である。なお、本実施形態では、図1に示すように半導体基板1の上側から光を入射させ、半導体基板1の下側から信号電荷を読み出す構成である。以下の説明では、半導体基板における、入射光が入射する側をの裏面側とし、入射光が入射する側とは反対側を表面側とする。また、回路基板2においては、半導体基板1側を裏面側とする。   The back-illuminated imaging element 10 generates signal charges by photoelectrically converting incident light irradiated from one surface side of the semiconductor substrate 1, and reads out the signal charges from the other surface side of the semiconductor substrate 1 for imaging. It is the structure which performs. In the present embodiment, as shown in FIG. 1, light is incident from the upper side of the semiconductor substrate 1 and signal charges are read from the lower side of the semiconductor substrate 1. In the following description, the side on which incident light is incident on the semiconductor substrate is referred to as the back side, and the side opposite to the side on which incident light is incident is referred to as the front side. In the circuit board 2, the semiconductor substrate 1 side is the back side.

半導体基板1は、n型のシリコン層16と、n型のシリコン層16よりも不純物濃度の高いn+型からなる光電変換層として機能する不純物拡散層PDとを有している。半導体基板1の表面側には、不純物拡散層PDで生成された信号電荷を蓄積させることができる電荷転送領域18と、該電荷転送領域18が設けられた画素と隣り合う他の画素との間に設けられた素子分離領域15とが形成されている。   The semiconductor substrate 1 has an n-type silicon layer 16 and an impurity diffusion layer PD functioning as an n + type photoelectric conversion layer having an impurity concentration higher than that of the n-type silicon layer 16. On the front surface side of the semiconductor substrate 1, there is a space between the charge transfer region 18 in which the signal charge generated in the impurity diffusion layer PD can be accumulated and another pixel adjacent to the pixel provided with the charge transfer region 18. And an element isolation region 15 provided in.

半導体基板1の表面には絶縁層13が設けられ、更に、該絶縁層13を介して回路基板2が設けられている。回路基板2は絶縁層11を有している。回路基板2の該絶縁層11の裏面側には、ポリシリコン等によって構成された電荷捕集電極12と、転送時に電圧が印加され、不純物拡散層PDに蓄積された信号電荷を転送する電荷転送電極14とが設けられている。電荷捕集電極12の作用については、後述する。   An insulating layer 13 is provided on the surface of the semiconductor substrate 1, and a circuit board 2 is further provided via the insulating layer 13. The circuit board 2 has an insulating layer 11. On the back side of the insulating layer 11 of the circuit board 2, a charge collection electrode 12 made of polysilicon or the like, and a charge transfer for transferring a signal charge accumulated in the impurity diffusion layer PD by applying a voltage at the time of transfer. An electrode 14 is provided. The operation of the charge collection electrode 12 will be described later.

半導体基板1のn型のシリコン層16の裏面側には、n型のシリコン層16よりも不純物濃度の低いn−型のシリコン層17が形成されている。シリコン層17の裏面側には、入射光に対して透明な絶縁層18が形成され、また、絶縁層18の裏面側には、該絶縁層18とシリコン層17との屈折率差に起因する半導体基板の下面での光の反射を防止するために、窒化シリコンやダイヤモンド構造炭素膜等の入射光に対して透明な高屈折率層19が形成されている。   An n − type silicon layer 17 having an impurity concentration lower than that of the n type silicon layer 16 is formed on the back side of the n type silicon layer 16 of the semiconductor substrate 1. An insulating layer 18 that is transparent to incident light is formed on the back side of the silicon layer 17, and due to a difference in refractive index between the insulating layer 18 and the silicon layer 17 on the back side of the insulating layer 18. In order to prevent reflection of light on the lower surface of the semiconductor substrate, a high refractive index layer 19 that is transparent to incident light such as silicon nitride or a diamond structure carbon film is formed.

高屈折率層19の上には、画素ごとにR(赤)、G(緑)、B(青)のいずれか1つが所定のパターンで配置されてなるカラーフィルタ層21が形成されている。カラーフィルタ層21の上には、上方に突出する湾曲面を有する上凸レンズ形状のマイクロレンズ層22が形成されている。なお、マイクロレンズ層22は設けずに、高屈折率層19の上にカラーフィルタ層21のみを形成した構成としてもよい。   On the high refractive index layer 19, a color filter layer 21 in which any one of R (red), G (green), and B (blue) is arranged in a predetermined pattern for each pixel is formed. On the color filter layer 21, an upward convex lens-shaped microlens layer 22 having a curved surface protruding upward is formed. Note that the microlens layer 22 may be omitted, and only the color filter layer 21 may be formed on the high refractive index layer 19.

図2は、本実施形態の裏面照射型撮像素子の一部を示す平面図である。図2では、絶縁層11の裏面側に設けられた電荷捕集電極12と電荷転送電極14とを説明するため、その他の部分は省略又は簡略して示している。電荷捕集電極12は、図中破線で格子状に区画される複数の画素領域において、各画素領域の中央近傍に設けられている。電荷転送電極14は、電荷転送領域18を形成した領域の下に形成され、その一部が電荷捕集電極12の近接する位置まで延設されている。   FIG. 2 is a plan view showing a part of the backside illumination type imaging device of the present embodiment. In FIG. 2, in order to describe the charge collection electrode 12 and the charge transfer electrode 14 provided on the back surface side of the insulating layer 11, other portions are omitted or simplified. The charge collection electrode 12 is provided in the vicinity of the center of each pixel region in a plurality of pixel regions partitioned in a grid pattern by broken lines in the drawing. The charge transfer electrode 14 is formed under the region where the charge transfer region 18 is formed, and a part of the charge transfer electrode 14 extends to a position close to the charge collection electrode 12.

本実施形態において、画素とは、撮像画像を構成する最小単位の領域を意味し、RGBのそれぞれのカラーフィルタ層21と、各カラーフィルタ層21の下に設けられた不純物拡散層PDとを含む。また、各画素ごとに電荷捕集電極12、電荷転送電極14、電荷転送領域18が形成されている。   In the present embodiment, a pixel means a minimum unit area constituting a captured image, and includes RGB color filter layers 21 and impurity diffusion layers PD provided under each color filter layer 21. . In addition, a charge collection electrode 12, a charge transfer electrode 14, and a charge transfer region 18 are formed for each pixel.

電荷捕集電極12には、撮像時及び電荷読み出し時に電圧を印加する電圧供給部31が接続され、また、電荷転送電極14には、電荷読み出し時に電圧を印加する電圧供給部32が接続されている。   The charge collection electrode 12 is connected to a voltage supply unit 31 that applies a voltage at the time of imaging and charge readout, and the charge transfer electrode 14 is connected to a voltage supply unit 32 that applies a voltage at the time of charge readout. Yes.

電荷捕集電極12と電荷転送電極14はそれぞれ、別のポリシリコンで構成されていてもよく、又は同じポリシリコンをパターン形成することで同時に形成してもよい。   Each of the charge collection electrode 12 and the charge transfer electrode 14 may be made of different polysilicon, or may be formed simultaneously by patterning the same polysilicon.

図3は、本実施形態の裏面照射型撮像素子の撮像時の状態を説明する断面図である。図4は、本実施形態の裏面照射型撮像素子の電荷読み出し時の状態を説明する断面図である。
裏面照射型撮像素子10は、撮像時には、入射光がマイクロレンズ層22を透過し、該カラーフィルタ層21を透過した入射光に応じて不純物拡散層PDにおける光電変換によって信号電荷が生成される。図3に示すように、本実施形態の裏面照射型撮像素子10では、撮像時においては電荷捕集電極12に所定の正電位の電圧が印加され、不純物拡散層PDで生成された信号電荷を構成する電子が、電荷捕集電極12側に誘導される。そして、電荷捕集電極12の電位を一定にすることで、誘導された電子が不純物拡散層PDにおける表面側近傍で捕集された状態のまま維持される。
FIG. 3 is a cross-sectional view illustrating a state during imaging of the backside illumination type imaging device of the present embodiment. FIG. 4 is a cross-sectional view illustrating a state at the time of charge reading of the backside illumination type imaging device of the present embodiment.
In the back-illuminated image sensor 10, during imaging, incident light is transmitted through the microlens layer 22, and signal charges are generated by photoelectric conversion in the impurity diffusion layer PD according to the incident light transmitted through the color filter layer 21. As shown in FIG. 3, in the backside illumination type imaging device 10 of the present embodiment, a predetermined positive potential voltage is applied to the charge collection electrode 12 during imaging, and the signal charge generated in the impurity diffusion layer PD is changed. The constituting electrons are guided to the charge collection electrode 12 side. Then, by making the electric potential of the charge collection electrode 12 constant, the induced electrons are maintained in a state of being collected in the vicinity of the surface side in the impurity diffusion layer PD.

図4に示す電荷読み出し時には、電荷転送電極14と電荷捕集電極12との両方に所定の電圧を印加することで、半導体基板1の、電荷転送電極14及び電荷捕集電極12の上方に電位ポテンシャルが形成される。ここで、電荷転送電極14の電位を電荷捕集電極12の電位より大きくするため、電荷捕集電極12側から電荷転送電極14側へ電位が高くなる電位ポテンシャルの傾斜が形成され、信号電荷の電子が電荷転送電極14側へ誘導され、該電荷転送電極14の上方に形成された電荷転送領域18に移される。   At the time of reading the charge shown in FIG. 4, a predetermined voltage is applied to both the charge transfer electrode 14 and the charge collection electrode 12, so that the potential on the semiconductor substrate 1 above the charge transfer electrode 14 and the charge collection electrode 12 is increased. A potential is formed. Here, in order to make the potential of the charge transfer electrode 14 larger than the potential of the charge collection electrode 12, a potential potential gradient is formed so that the potential increases from the charge collection electrode 12 side to the charge transfer electrode 14 side. Electrons are guided toward the charge transfer electrode 14 and transferred to a charge transfer region 18 formed above the charge transfer electrode 14.

図5は、電荷読み出し時の電圧供給部から印加される電圧を示すグラフである。電荷読み出し時には、電圧供給部31,32が、電荷捕集電極12と電荷転送電極14に所定の電圧差VDでそれぞれ電圧VH,VLを印加し、信号電荷を電荷転送領域18に誘導している。電圧供給部31,32の電圧差VDを大きくすることで、信号電荷を円滑的に誘導でき、不純物拡散層PDに残ってしまう信号電荷の量を低減することができるため、転送効率が良い。ここで、電荷捕集電極12に印加する電圧VLを電荷転送電極14に印加する電圧VHに対して十分に低くすることで、電荷転送電極14に印加する最大電圧の値をできるだけ小さくすることができ、この結果、電荷転送電極14を駆動するための電源電圧を低くすることができる。   FIG. 5 is a graph showing the voltage applied from the voltage supply unit during charge reading. During charge reading, the voltage supply units 31 and 32 apply voltages VH and VL to the charge collection electrode 12 and the charge transfer electrode 14 with a predetermined voltage difference VD, respectively, to induce signal charges to the charge transfer region 18. . By increasing the voltage difference VD between the voltage supply units 31 and 32, the signal charge can be smoothly induced and the amount of the signal charge remaining in the impurity diffusion layer PD can be reduced, so that the transfer efficiency is good. Here, by making the voltage VL applied to the charge collection electrode 12 sufficiently lower than the voltage VH applied to the charge transfer electrode 14, the value of the maximum voltage applied to the charge transfer electrode 14 can be made as small as possible. As a result, the power supply voltage for driving the charge transfer electrode 14 can be lowered.

なお、本発明は、前述した実施形態に限定されるものではなく、適宜変形、改良などが可能である。
例えば、上記実施形態では、信号電荷を読み出す構成をCCD型の読み出し構成としたがこれに限定されず、CMOS型の読出回路を備えていてもよい。
In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
For example, in the above-described embodiment, the configuration for reading signal charges is a CCD-type readout configuration, but the present invention is not limited to this, and a CMOS-type readout circuit may be provided.

本発明にかかる裏面照射型撮像素子の一実施形態の構成を示す断面図である。It is sectional drawing which shows the structure of one Embodiment of the backside illumination type image pick-up element concerning this invention. 裏面照射型撮像素子の一部を示す平面図である。It is a top view which shows a part of back irradiation type imaging device. 裏面照射型撮像素子の撮像時の状態を説明する断面図である。It is sectional drawing explaining the state at the time of the imaging of a back irradiation type imaging device. 裏面照射型撮像素子の電荷読み出し時の状態を説明する断面図である。It is sectional drawing explaining the state at the time of the charge read-out of a back irradiation type imaging device. 電荷読み出し時の電圧供給部から印加される電圧を示すグラフである。It is a graph which shows the voltage applied from the voltage supply part at the time of charge reading.

符号の説明Explanation of symbols

1 半導体基板
2 回路基板
10 裏面照射型撮像素子
12 電荷捕集電極
14 電荷転送電極
18 電荷転送領域
PD 不純物拡散領域
DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Circuit board 10 Back surface illumination type image pick-up element 12 Charge collection electrode 14 Charge transfer electrode 18 Charge transfer region PD Impurity diffusion region

Claims (4)

半導体基板の裏面側から光を照射し、入射光に応じて前記半導体基板内で発生した電荷を、前記半導体基板の表面側から読み出して撮像を行う裏面照射型撮像素子であって、
前記半導体基板に設けられ、入射光を光電変換することで信号電荷を生成する不純物拡散層と、
前記半導体基板の表面側に形成された回路基板と、
前記半導体基板の表面側に設けられ、信号電荷を転送する電荷転送領域とを備え、
前記回路基板に、撮像時に電圧が印加されることで、前記不純物拡散層で生成される信号電荷を前記半導体基板の表面側に捕集する電荷捕集電極を備えていることを特徴とする裏面照射型撮像素子。
A backside illuminating type imaging device that irradiates light from the back side of the semiconductor substrate, reads out the charge generated in the semiconductor substrate in response to incident light from the front side of the semiconductor substrate, and performs imaging,
An impurity diffusion layer that is provided on the semiconductor substrate and generates signal charges by photoelectrically converting incident light; and
A circuit board formed on the surface side of the semiconductor substrate;
A charge transfer region provided on the surface side of the semiconductor substrate and transferring a signal charge;
A back surface comprising a charge collection electrode that collects a signal charge generated in the impurity diffusion layer on the front side of the semiconductor substrate when a voltage is applied to the circuit board during imaging. Irradiation type image sensor.
前記回路基板の裏面側に、信号電荷を転送する電圧が印加される電荷転送電極が設けられ、電荷転送時に、前記電荷捕集電極と前記電荷転送電極にそれぞれ電圧を印加し、信号電荷を前記電荷転送領域に誘導する電圧供給部が設けられていることを特徴とする請求項1に記載の裏面照射型撮像素子。   A charge transfer electrode to which a voltage for transferring a signal charge is applied is provided on the back side of the circuit board, and at the time of charge transfer, a voltage is applied to the charge collection electrode and the charge transfer electrode, respectively. The backside illuminated imaging device according to claim 1, further comprising a voltage supply unit that induces the charge transfer region. 半導体基板の裏面側から光を照射し、入射光に応じて前記半導体基板内で発生した電荷を、前記半導体基板の表面側から読み出して撮像を行う裏面照射型撮像素子の駆動方法であって、
前記裏面照射型撮像素子に、入射光を光電変換することで信号電荷を生成するため前記半導体基板に設けられた不純物拡散層と、前記半導体基板の表面側に形成された回路基板と、前記半導体基板の表面側に設けられ、信号電荷を転送する電荷転送領域とが備えられ、
撮像時に、前記回路基板に設けられた電荷捕集電極に電圧を印加することで、前記不純物拡散層で生成される信号電荷を前記半導体基板の表面側に捕集することを特徴とする裏面照射型撮像素子の駆動方法。
A method for driving a backside illuminating type imaging device that irradiates light from the back side of a semiconductor substrate, reads out charges generated in the semiconductor substrate in response to incident light from the front side of the semiconductor substrate, and performs imaging,
Impurity diffusion layers provided on the semiconductor substrate for generating signal charges by photoelectrically converting incident light into the back-illuminated image sensor, a circuit substrate formed on the front side of the semiconductor substrate, and the semiconductor A charge transfer region provided on the surface side of the substrate and transferring a signal charge,
Backside illumination characterized by collecting signal charges generated by the impurity diffusion layer on the front side of the semiconductor substrate by applying a voltage to a charge collection electrode provided on the circuit board during imaging Type image sensor driving method.
前記回路基板の裏面側に、信号電荷を転送する駆動電圧が印加される電荷転送電極が設けられ、電荷転送時に、前記電荷捕集電極と前記電荷転送電極にそれぞれ電圧を印加することで、信号電荷を前記電荷転送領域に誘導することを特徴とする請求項3に記載の裏面照射型撮像素子の駆動方法。   A charge transfer electrode to which a drive voltage for transferring a signal charge is applied is provided on the back side of the circuit board, and a signal is applied by applying a voltage to each of the charge collection electrode and the charge transfer electrode during charge transfer. The method of driving a backside illuminating type image pickup device according to claim 3, wherein charge is guided to the charge transfer region.
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