JPH04245474A - Solid-state image pick-up element - Google Patents
Solid-state image pick-up elementInfo
- Publication number
- JPH04245474A JPH04245474A JP3010047A JP1004791A JPH04245474A JP H04245474 A JPH04245474 A JP H04245474A JP 3010047 A JP3010047 A JP 3010047A JP 1004791 A JP1004791 A JP 1004791A JP H04245474 A JPH04245474 A JP H04245474A
- Authority
- JP
- Japan
- Prior art keywords
- light
- film
- shielding film
- layer
- reflection
- 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.)
- Pending
Links
- 239000000758 substrate Substances 0.000 claims abstract description 23
- 239000011229 interlayer Substances 0.000 claims abstract description 16
- 239000004065 semiconductor Substances 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 2
- 239000010410 layer Substances 0.000 abstract description 17
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 6
- 229910021417 amorphous silicon Inorganic materials 0.000 abstract description 5
- 229910045601 alloy Inorganic materials 0.000 abstract description 3
- 239000000956 alloy Substances 0.000 abstract description 3
- 238000000034 method Methods 0.000 abstract description 3
- 238000005546 reactive sputtering Methods 0.000 abstract description 2
- 230000003449 preventive effect Effects 0.000 abstract 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract 1
- 229910052782 aluminium Inorganic materials 0.000 abstract 1
- 230000015572 biosynthetic process Effects 0.000 abstract 1
- 229910000838 Al alloy Inorganic materials 0.000 description 6
- 238000003384 imaging method Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 238000005468 ion implantation Methods 0.000 description 2
- 238000002161 passivation Methods 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 238000000151 deposition Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
Landscapes
- Solid State Image Pick-Up Elements (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は固体撮像素子に関し、特
に遮光膜の上下に反射防止膜を積層した固体撮像素子に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image sensor, and more particularly to a solid-state image sensor in which anti-reflection films are laminated above and below a light-shielding film.
【０００２】0002
【従来の技術】従来、ＣＣＤ固体撮像素子は、外観上、
複数の垂直ＣＣＤ部１と、これらの垂直ＣＣＤ部１間に
配置された感光部２と、水平ＣＣＤ部３と、出力部４と
から構成されている（図３図示）。こうした固体撮像素
子は、断面的に見れば、図２に示すようになっている。[Prior Art] Conventionally, CCD solid-state image sensors have the following appearance:
It is composed of a plurality of vertical CCD sections 1, a photosensitive section 2 disposed between these vertical CCD sections 1, a horizontal CCD section 3, and an output section 4 (as shown in FIG. 3). A cross-sectional view of such a solid-state image sensor is as shown in FIG.
【０００３】図中の１１は、ｐ型のシリコン（Ｓｉ）基
板である。この基板１１の表面には、感光部であるｎ−
型のフォトダイオ−ド層１２、このフォトダイオ−ド
で光電変換された電荷を転送するｎ型の電荷転送路１３
及びｐ＋ 型のチャネルストッパ層１４等がイオン打込
みなどにより形成されている。前記基板１１上には、ゲ
−ト酸化膜１５を介して多結晶シリコンからなる電極１
６が形成されている。
この電極１６を含むゲ−ト酸化膜１５上には、層間絶縁
膜１７が形成されている。この層間絶縁膜１７上でかつ
前記電荷転送路１３に対応する位置には、スミア防止の
ためアルミ系合金からなる遮光膜１８が形成されている
。この遮光膜１８を含む層間絶縁膜１７上には、パッシ
ベ−ション膜１９が形成されている。Reference numeral 11 in the figure represents a p-type silicon (Si) substrate. On the surface of this substrate 11, there is an n-
type photodiode layer 12, and an n-type charge transfer path 13 for transferring charges photoelectrically converted by this photodiode.
A p+ type channel stopper layer 14 and the like are formed by ion implantation or the like. An electrode 1 made of polycrystalline silicon is placed on the substrate 11 with a gate oxide film 15 interposed therebetween.
6 is formed. An interlayer insulating film 17 is formed on the gate oxide film 15 including the electrode 16. On this interlayer insulating film 17 and at a position corresponding to the charge transfer path 13, a light shielding film 18 made of an aluminum alloy is formed to prevent smearing. A passivation film 19 is formed on the interlayer insulating film 17 including the light shielding film 18.
【０００４】0004
【発明が解決しようとする課題】しかしながら、従来の
ＣＣＤ固体撮像素子によれば、遮光膜１８として反射率
の高いアルミ系合金を用いているため、遮光膜１８の端
部で乱反射した光が隣の電荷転送路１３を感光してスミ
アが発生する。また、光が遮光膜１８とＳｉ基板１１と
の間の層間絶縁膜１７を通して入射し、Ｓｉ基板表面と
遮光膜１８との間で多重反射して伝わり（導波管効果）
、その結果光が電荷転送路１３へ入射してスミアが発生
する。こうした事実は、電子情報通信学会論文誌１９８
９／９，Ｖｏｌ．Ｊ７２−Ｃ−ＩＩ，Ｎｏ．９で明らか
である。[Problems to be Solved by the Invention] However, in the conventional CCD solid-state image sensor, since an aluminum alloy with a high reflectance is used as the light-shielding film 18, the light diffusely reflected at the edge of the light-shielding film 18 may be reflected from the adjacent light. Smear occurs when the charge transfer path 13 is exposed to light. Furthermore, light enters through the interlayer insulating film 17 between the light shielding film 18 and the Si substrate 11, and is propagated through multiple reflections between the Si substrate surface and the light shielding film 18 (waveguide effect).
As a result, light enters the charge transfer path 13 and smear occurs. These facts are true in IEICE Transactions 198
9/9, Vol. J72-C-II, No. 9 is clear.
【０００５】こうしたことから、層間絶縁膜１７の厚さ
を薄くしたり、電極１６と遮光膜１８端までの距離（遮
光長さ）を長くする方法が提案されている。しかし、電
極１６と遮光膜との短絡が生じたり、感光部の開口が狭
くなって感度低下が生じたりする。[0005] For these reasons, methods have been proposed to reduce the thickness of the interlayer insulating film 17 and to increase the distance between the electrode 16 and the end of the light shielding film 18 (light shielding length). However, a short circuit between the electrode 16 and the light-shielding film may occur, or the aperture of the photosensitive portion may become narrow, resulting in a decrease in sensitivity.
【０００６】本発明は上記事情に鑑みてなされたもので
、遮光膜の上下に反射防止膜を設けることにより、遮光
膜の端部での光の乱反射や遮光膜と基板表面との間で反
射を繰り返して光が伝わる導波管効果により電荷転送路
が感光されて生じるスミアを抑制できる固体撮像素子を
提供することを目的とする。The present invention has been made in view of the above circumstances, and by providing anti-reflection films above and below a light-shielding film, diffused reflection of light at the edges of the light-shielding film and reflection between the light-shielding film and the substrate surface can be prevented. It is an object of the present invention to provide a solid-state imaging device that can suppress smear caused by exposure of a charge transfer path to light due to the waveguide effect in which light propagates repeatedly.
【０００７】[0007]
【課題を解決するための手段】本発明は、光電変換する
感光部及びこの感光部で光電変換された電荷を転送する
電荷転送路を表面に有した半導体基板と、この半導体基
板上に該基板と電気的に絶縁して形成された電極と、こ
の電極を含む前記半導体基板上に層間絶縁膜を介して前
記電極の上方に位置するように形成された遮光膜と、こ
の遮光膜を上下から挾む反射防止膜とを具備することを
特徴とする固体撮像素子である。本発明において、反射
防止膜の材質としては、アモルファス（α）Ｓｉ、Ｔｉ
Ｎ、Ｗなどが挙げられ、遮光膜の上下の反射防止膜の材
質をそれぞれ別々にしてもよいし、同じにしても良い。
本発明において、遮光膜の材質としては、反射率の高い
アルミ系合金等が挙げられる。[Means for Solving the Problems] The present invention provides a semiconductor substrate having a photosensitive section for photoelectric conversion and a charge transfer path for transferring the charges photoelectrically converted in the photosensitive section, and a substrate on the semiconductor substrate. a light-shielding film formed on the semiconductor substrate including the electrode so as to be located above the electrode via an interlayer insulating film; The present invention is a solid-state imaging device characterized by comprising an antireflection film sandwiched therebetween. In the present invention, the material of the anti-reflection film is amorphous (α)Si, Ti
Examples include N and W, and the antireflection films on the upper and lower sides of the light shielding film may be made of different materials, or may be the same material. In the present invention, examples of the material of the light-shielding film include aluminum alloys with high reflectance.
【０００８】[0008]
【作用】本発明においては、遮光膜が、下部の第１反射
防止膜と、上部の第２反射防止膜により挾まれた構成に
なっている。従って、従来のように遮光膜の端部に当た
って乱反射した光は、本願発明では第２反射防止膜２９
ｂに当たるため、乱反射を防止され、スミアの発生を抑
制できる。[Operation] In the present invention, the light shielding film is sandwiched between a first antireflection film at the bottom and a second antireflection film at the top. Therefore, in the present invention, the light that hits the end of the light shielding film and is diffusely reflected as in the conventional case is removed from the second antireflection film 29.
b, thus preventing diffused reflection and suppressing the occurrence of smear.
【０００９】また、遮光膜の下側に形成された第２反射
防止膜の存在により、基板と遮光膜間の層間絶縁膜を光
が入射しても、第２反射防止膜により光を減衰させ、こ
れによりスミアの発生を抑制できる。そして、従来より
も光の反射の減衰を早くして導波管効果が抑えられるた
めに、遮光長さを小さくして受光部の開口を広げること
ができ、感度を向上できる。更に、層間絶縁膜も極端に
薄くする必要がなくなるため、電極と遮光膜間の短絡を
防止できる。Furthermore, due to the presence of the second anti-reflection film formed under the light-shielding film, even if light enters the interlayer insulating film between the substrate and the light-shielding film, the second anti-reflection film attenuates the light. , thereby suppressing the occurrence of smear. Furthermore, since the waveguide effect is suppressed by attenuating light reflection faster than in the past, the light shielding length can be reduced and the aperture of the light receiving section can be widened, thereby improving sensitivity. Furthermore, since there is no need to make the interlayer insulating film extremely thin, short circuits between the electrodes and the light shielding film can be prevented.
【００１０】0010
【実施例】以下、本発明の一実施例に係るＣＣＤ固体撮
像素子について図１を参照して説明する。Embodiment A CCD solid-state imaging device according to an embodiment of the present invention will be described below with reference to FIG.
【００１１】図中の２１は、ｐ型のシリコン（Ｓｉ）基
板である。この基板２１の表面には、感光部であるｎ−
型のフォトダイオ−ド層２２、このフォトダイオ−ド
で光電変換された電荷を転送するｎ型の電荷転送路２３
及びｐ＋ 型のチャネルストッパ層２４等がイオン打込
みなどにより形成されている。前記基板２１上には、ゲ
−ト酸化膜２５を介して多結晶シリコンからなる電極２
６が形成されている。
この電極２６を含むゲ−ト酸化膜２５上には、層間絶縁
膜２７が形成されている。この層間絶縁膜２７上でかつ
前記電荷転送路２３の略真上に対応する位置には、スミ
ア防止のためアルミ系合金からなる遮光膜２８が形成さ
れている。この遮光膜２８の上下には、例えばＴｉＮか
らなる第１反射防止膜２９ａ，アモルファスＳｉからな
る第２反射防止膜２９ｂが形成されている。ここで、Ｔ
ｉとＮ２ との反応性スパッタリングによりＴｉＮ層を
堆積し、その上にアルミ系合金層を形成した後、ＴｉＮ
層，合金層をパタ−ニングして第１反射防止膜２９ａ，
遮光膜２８を形成し、更にアモルファスＳｉ層をｐ−Ｃ
ＶＤ法により堆積した後パタ−ニングして第２反射防止
膜２９ｂを形成する。21 in the figure is a p-type silicon (Si) substrate. On the surface of this substrate 21, there is an n-
type photodiode layer 22, and an n-type charge transfer path 23 for transferring charges photoelectrically converted by this photodiode.
A p+ type channel stopper layer 24 and the like are formed by ion implantation or the like. An electrode 2 made of polycrystalline silicon is placed on the substrate 21 with a gate oxide film 25 interposed therebetween.
6 is formed. An interlayer insulating film 27 is formed on the gate oxide film 25 including the electrode 26. A light shielding film 28 made of an aluminum alloy is formed on the interlayer insulating film 27 and at a position substantially directly above the charge transfer path 23 to prevent smearing. Above and below this light shielding film 28, a first antireflection film 29a made of, for example, TiN and a second antireflection film 29b made of amorphous Si are formed. Here, T
After depositing a TiN layer by reactive sputtering of i and N2 and forming an aluminum alloy layer thereon, TiN
layer and alloy layer to form a first antireflection film 29a,
A light shielding film 28 is formed, and an amorphous Si layer is formed with p-C.
After being deposited by the VD method, it is patterned to form a second antireflection film 29b.
【００１２】しかして、上記実施例に係るＣＣＤ固体撮
像素子は、アルミ系合金からなる遮光膜２８が、例えば
ＴｉＮからなる第１反射防止膜２９ａと、アモルファス
Ｓｉからなる第２反射防止膜２９ｂにより挾まれた構成
になっている。従って、従来のように遮光膜の端部に当
たる光は、本願発明では第２反射防止膜２９ｂに当たる
ため、乱反射を防止され、スミアの発生を抑制できる。[0012] In the CCD solid-state imaging device according to the above embodiment, the light-shielding film 28 made of an aluminum alloy is composed of a first anti-reflection film 29a made of, for example, TiN and a second anti-reflection film 29b made of amorphous Si. It has a narrow composition. Therefore, in the present invention, the light that hits the end of the light-shielding film as in the conventional case hits the second anti-reflection film 29b, thereby preventing diffuse reflection and suppressing the occurrence of smear.
【００１３】また、遮光膜２８の下側に形成された第２
反射防止膜２９ｂの存在により、Ｓｉ基板と光遮蔽幕２
８間の層間絶縁膜２７を光が入射しても、第２反射防止
膜２９ｂにより光を減衰させ、これによりスミアの発生
を抑制できる。そして、従来よりも光の反射の減衰を早
くして導波管効果が抑えられるために、遮光長さを小さ
くして受光部の開口を広げることができ、感度を向上で
きる。更に、層間絶縁膜２７も極端に薄くする必要がな
くなるため、電極２６と遮光膜２８間の短絡を防止でき
る。[0013] Also, a second
Due to the presence of the anti-reflection film 29b, the Si substrate and the light shielding curtain 2
Even if light enters the interlayer insulating film 27 between the two layers, the second antireflection film 29b attenuates the light, thereby suppressing the occurrence of smear. Furthermore, since the waveguide effect is suppressed by attenuating light reflection faster than in the past, the light shielding length can be reduced and the aperture of the light receiving section can be widened, thereby improving sensitivity. Furthermore, since the interlayer insulating film 27 does not need to be made extremely thin, short circuits between the electrode 26 and the light shielding film 28 can be prevented.
【００１４】[0014]
【発明の効果】以上詳述した如く本発明によれば、遮光
膜の上下に反射防止膜を設けることにより、遮光膜の端
部での光の乱反射や遮光膜と基板表面との間で反射を繰
り返して光が伝わる導波管効果により電荷転送路が感光
されて生じるスミアを抑制でき、更には遮光長さを小さ
くし受光部の開口を広げることにより感度を向上でき、
かつ層間絶縁膜も極端に薄くする必要がなく電極と遮光
膜間の短絡を防止可能な固体撮像素子を提供できる。As detailed above, according to the present invention, by providing anti-reflection films above and below a light-shielding film, diffused reflection of light at the edges of the light-shielding film and light reflection between the light-shielding film and the substrate surface can be prevented. The waveguide effect in which light propagates repeatedly can suppress the smear that occurs when the charge transfer path is exposed to light, and furthermore, the sensitivity can be improved by reducing the light shielding length and widening the aperture of the light receiving part.
Moreover, there is no need to make the interlayer insulating film extremely thin, and it is possible to provide a solid-state imaging device that can prevent short circuits between the electrodes and the light-shielding film.
【図１】本発明の一実施例に係るＣＣＤ固体撮像素子の
断面図。FIG. 1 is a cross-sectional view of a CCD solid-state image sensor according to an embodiment of the present invention.
【図２】ＣＣＤ固体撮像素子の全体説明図。FIG. 2 is an overall explanatory diagram of a CCD solid-state image sensor.
【図３】従来のＣＣＤ固体撮像素子の断面図。FIG. 3 is a cross-sectional view of a conventional CCD solid-state image sensor.
２１…ｐ型のシリコン基板、２２…フォトダイオ−ド層
、２３…電荷転送路、２６…電極、２７…層間絶縁膜、
２８…遮光膜、２９ａ，２９ｂ…反射防止膜、３０…パ
ッシベ−ション膜。21... P-type silicon substrate, 22... Photodiode layer, 23... Charge transfer path, 26... Electrode, 27... Interlayer insulating film,
28... Light shielding film, 29a, 29b... Antireflection film, 30... Passivation film.
Claims (1)
光電変換された電荷を転送する表面に電荷転送路を有し
た半導体基板と、この半導体基板上に該基板と電気的に
絶縁して形成された電極と、この電極を含む前記半導体
基板上に層間絶縁膜を介して前記電極の上方に位置する
ように形成された遮光膜と、この遮光膜を上下から挾む
反射防止膜とを具備することを特徴とする固体撮像素子
。1. A semiconductor substrate having a photosensitive section that performs photoelectric conversion and a charge transfer path on the surface that transfers the charges photoelectrically converted in the photosensitive section, and a semiconductor substrate formed on the semiconductor substrate and electrically insulated from the substrate. a light shielding film formed on the semiconductor substrate including the electrode so as to be located above the electrode via an interlayer insulating film, and an antireflection film sandwiching the light shielding film from above and below. A solid-state image sensor characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3010047A JPH04245474A (en) | 1991-01-30 | 1991-01-30 | Solid-state image pick-up element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3010047A JPH04245474A (en) | 1991-01-30 | 1991-01-30 | Solid-state image pick-up element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04245474A true JPH04245474A (en) | 1992-09-02 |
Family
ID=11739487
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3010047A Pending JPH04245474A (en) | 1991-01-30 | 1991-01-30 | Solid-state image pick-up element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04245474A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6188119B1 (en) | 1997-02-10 | 2001-02-13 | Nec Corporation | Semiconductor device having barrier metal layer between a silicon electrode and metal electrode and manufacturing method for same |
| JP2017092499A (en) * | 2017-02-10 | 2017-05-25 | キヤノン株式会社 | Solid state imaging device and imaging system |
-
1991
- 1991-01-30 JP JP3010047A patent/JPH04245474A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6188119B1 (en) | 1997-02-10 | 2001-02-13 | Nec Corporation | Semiconductor device having barrier metal layer between a silicon electrode and metal electrode and manufacturing method for same |
| JP2017092499A (en) * | 2017-02-10 | 2017-05-25 | キヤノン株式会社 | Solid state imaging device and imaging system |
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