JPH07325263A - Integral type condenser element for solid-state image pickup element and its production - Google Patents
Integral type condenser element for solid-state image pickup element and its productionInfo
- Publication number
- JPH07325263A JPH07325263A JP6142412A JP14241294A JPH07325263A JP H07325263 A JPH07325263 A JP H07325263A JP 6142412 A JP6142412 A JP 6142412A JP 14241294 A JP14241294 A JP 14241294A JP H07325263 A JPH07325263 A JP H07325263A
- Authority
- JP
- Japan
- Prior art keywords
- refractive index
- index distribution
- photoelectric conversion
- distribution region
- light
- 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.)
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、略輪帯状の光電変換部
を有する画素で構成される固体撮像素子の感度向上のた
めの光学素子に係り、特に固体撮像素子の不感領域への
入射光を光電変換部へ集光させることにより感度向上を
図ることとした、固体撮像素子上に一体に形成される固
体撮像素子用一体型集光素子およびその製造方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element for improving the sensitivity of a solid-state image pickup device composed of pixels having a substantially annular photoelectric conversion portion, and more particularly to an incident light to a dead region of the solid-state image pickup device. The present invention relates to an integrated light-collecting device for a solid-state imaging device, which is integrally formed on a solid-state imaging device, and a method for manufacturing the same, in which the sensitivity is improved by condensing light onto a photoelectric conversion unit.
【０００２】[0002]
【従来の技術】ＣＣＤ（Charge Coupled Device ）のよ
うな固体撮像素子上の各画素は、主に、矩形の光電変換
部と信号の読み出し回路部との二つの領域からなってい
る。このうち、信号の読み出し回路部上は入射光成分に
対する不感領域である。この不感領域上に入射する光成
分を光電変換部に集光し、撮像素子の高感度化を達成す
るとともに、他の素子特性を劣化させない有効な手段の
一つとして、固体撮像素子上に透明なレンズアレイを配
置し、不感領域である信号読み出し回路部上に到達する
入射光成分を光電変換部に集光させるようにした、一体
型の凸または凹のマイクロレンズアレイが、特開昭５３
−７４３９５号公報に開示されている。2. Description of the Related Art Each pixel on a solid-state image pickup device such as a CCD (Charge Coupled Device) is mainly composed of two areas of a rectangular photoelectric conversion section and a signal reading circuit section. Of these, the signal readout circuit portion is an insensitive area to the incident light component. The light component incident on this dead region is condensed on the photoelectric conversion unit to achieve high sensitivity of the image sensor, and as one of the effective means that does not deteriorate other device characteristics, it is transparent on the solid-state image sensor. An integrated convex or concave microlens array in which an optical lens array is arranged so that an incident light component reaching a signal readout circuit portion, which is a dead area, is condensed in a photoelectric conversion portion is disclosed in Japanese Patent Laid-Open No. Sho 53-53.
-74395 gazette.
【０００３】また、ＣＭＤ（Charge Modulation Devic
e）のような輪帯状の光電変換部を有する固体撮像素子
においては、不感領域である輪帯状光電変換部の内径内
部および隣接する画素で囲まれた部分の真上に円錐状の
プリズムを設け、各不感領域に入射する光束を、断面に
おいて一定の幅で一定の角度に放射される円錐波に波面
変換し、輪帯状光電変換部に効率よく集光する方法が、
特開平３−１５０１０４号公報に開示されている。In addition, CMD (Charge Modulation Devic
In a solid-state imaging device having a ring-shaped photoelectric conversion unit as in e), a conical prism is provided inside the inner diameter of the ring-shaped photoelectric conversion unit which is a dead region and right above a portion surrounded by adjacent pixels. , A method of converting the light flux incident on each dead region into a conical wave radiated at a constant width and a constant angle in a cross section, and efficiently converging it on the annular photoelectric conversion unit,
It is disclosed in JP-A-3-150104.
【０００４】一方、マイクロレンズの各種収差を補正す
るためにマイクロレンズの一部に屈折率の分布を持たせ
る方法が、特開平２−８８４３３号公報に開示されてい
る。また、屈折率分布によってレンズ作用を有した平板
マイクロレンズの製造方法として、修飾酸化物を含有す
るガラス製の集光素子用基板を作製し、ここにマスクを
施した後、マスクを施さない露出部を溶融塩と接触さ
せ、溶融塩に含まれる金属イオンと集光素子用基板に含
まれる修飾酸化物をイオン交換することによって屈折率
に分布を付与させるマイクロレンズの製造方法が、特開
昭６１−２５１５４０号公報に開示されている。On the other hand, Japanese Patent Laid-Open No. 2-88433 discloses a method of providing a part of the microlens with a refractive index distribution in order to correct various aberrations of the microlens. In addition, as a method of manufacturing a flat plate microlens having a lens function depending on the refractive index distribution, a glass condensing element substrate containing a modified oxide was prepared, masked there, and then exposed without masking. A method for producing a microlens in which a refractive index is distributed by contacting a portion with a molten salt and ion-exchanging a metal ion contained in the molten salt and a modified oxide contained in a substrate for a light collecting element is disclosed in JP No. 61-251540.
【０００５】[0005]
【発明が解決しようとする課題】現在、固体撮像素子開
発上の大きな焦点となっているのは、画素の微細化によ
る素子の小型化および素子の高感度化である。しかし、
このような画素の微細化は、撮像素子の受光面積の減少
を伴う結果となり、必然的に光感度の低下という問題が
生じることになる。At present, a major focus in developing a solid-state image pickup device is miniaturization of a pixel and miniaturization of the device and increase in sensitivity of the device. But,
Such miniaturization of pixels results in a decrease in the light receiving area of the image pickup element, which inevitably causes a problem of a decrease in photosensitivity.
【０００６】このような問題点を解決するためには、特
開昭５３−７４３９５号公報に提案されているように、
各画素上にマイクロレンズを形成し、光電変換部に光束
を集光すればよい。この際、各画素の光電変換部の形状
が矩形である一般的な電荷結合素子（ＣＣＤ）の場合に
は、比較的単純な凸型または凹型のマイクロレンズアレ
イを用いることで十分である。しかしながら、光電変換
部の形状が輪帯状である固体撮像素子（例えばＣＭＤ）
の場合、例えば単純な凸形状のレンズを画素の真上に設
置した場合には、光電変換部の内径内部に集光された光
束は、内径内部が不感領域であるために感度向上に対し
て何ら影響を与えることがない。同様に、凹形状のレン
ズを各画素の間に設けることにより集光を行う場合に
も、不感領域である内径内部の真上から入射する光を利
用することができない。つまり、輪帯状の光電変換部を
有する固体撮像素子に対しては、単純な凸形状または凹
形状を有するマイクロレンズを画素上に形成しても素子
の高感度化を実現することはできなかった。In order to solve such a problem, as proposed in JP-A-53-74395,
A microlens may be formed on each pixel and the light flux may be condensed on the photoelectric conversion unit. At this time, in the case of a general charge-coupled device (CCD) in which the photoelectric conversion portion of each pixel has a rectangular shape, it is sufficient to use a relatively simple convex or concave microlens array. However, the solid-state imaging device (for example, CMD) in which the photoelectric conversion unit has a ring-shaped shape
In the case of, for example, when a simple convex lens is installed right above the pixel, the luminous flux condensed inside the inner diameter of the photoelectric conversion unit is not sensitive to the sensitivity improvement because the inner diameter is a dead area. It has no effect. Similarly, when a concave lens is provided between each pixel to collect light, it is not possible to use the light incident from directly above the inside of the inner diameter, which is a dead region. That is, for a solid-state imaging device having a ring-shaped photoelectric conversion unit, even if a microlens having a simple convex shape or a concave shape is formed on a pixel, high sensitivity of the element cannot be realized. .
【０００７】この欠点を解消するために、不感領域であ
る輪帯状の光電変換部の内径内部および各画素間に円錐
状のプリズムを形成する方法が、特開平５−１５０１０
４号公報に提案されているが、各画素の構造が微細であ
り、そこに形成された光電変換部の内径内部および各画
素間の不感領域は非常に狭い範囲であるため、この部分
に円錐状のプリズムを形成することは精度上、非常に困
難であった。In order to solve this drawback, a method of forming a conical prism inside the inner diameter of a ring-shaped photoelectric conversion portion which is a dead area and between each pixel is disclosed in Japanese Patent Laid-Open No. 5-15010.
However, since the structure of each pixel is minute and the dead area inside the photoelectric conversion portion formed therein and between the pixels is very narrow, a cone is formed in this portion. It was very difficult to form a prismatic shape in terms of accuracy.
【０００８】また、マイクロレンズを作製し、ここに屈
折率の分布を形成する方法が、特開平２−８８４３３号
公報に提案されているが、この方法はあくまで収差を補
正することだけを目的としており、不感領域に対する集
光が目的ではない。ＣＭＤのような輪帯状の光電変換部
に集光させるためには、さらに媒質中での光線の屈曲を
加味した分布形状でなくてはならない。Further, a method of producing a microlens and forming a distribution of refractive index therein is proposed in Japanese Patent Laid-Open No. 2-88433, but this method is only for correcting aberrations. However, the purpose is not to focus light on the dead area. In order to focus light on a ring-shaped photoelectric conversion unit such as CMD, the distribution shape must further include the bending of light rays in the medium.
【０００９】以上のように、従来の方法のみでは、輪帯
状の光電変換部を有する固体撮像素子の不感領域の入射
光成分を効率よく集光させ、素子の高感度化を実現する
ことは困難であった。As described above, it is difficult to increase the sensitivity of the element by efficiently condensing the incident light component in the dead area of the solid-state image pickup element having the ring-shaped photoelectric conversion portion only by the conventional method. Met.
【００１０】請求項１〜３に係る発明は、かかる従来の
問題点に鑑みてなされたもので、輪帯状の光電変換部を
有する固体撮像素子の不感領域の入射光成分を効率よく
集光させ、固体撮像素子の画素の微細化による素子の小
型化と高感度化を図ることができる固体撮像素子用一体
型集光素子およびその製造方法を提供することを目的と
する。The inventions according to claims 1 to 3 are made in view of the above-mentioned conventional problems, and efficiently collect the incident light component of the insensitive region of the solid-state image pickup device having the annular photoelectric conversion portion. An object of the present invention is to provide an integrated light-collecting device for a solid-state image pickup device, which is capable of achieving miniaturization and high sensitivity of the solid-state image pickup device due to miniaturization of pixels, and a manufacturing method thereof.
【００１１】[0011]
【課題を解決するための手段】上記課題を解決するため
に、請求項１に係る発明は、画素の光電変換部が略輪帯
状である固体撮像素子に一体に設けて用いる固体撮像素
子用一体型集光素子において、輪帯の中心を軸とした同
一軸上に正の屈折力を有する屈折率分布領域と負の屈折
力を有する屈折率分布領域とを備えることとした。In order to solve the above-mentioned problems, the invention according to claim 1 is for use in a solid-state image pickup device, wherein a photoelectric conversion portion of a pixel is provided integrally with a solid-state image pickup device having a substantially annular shape. In the body type light-collecting device, a refractive index distribution region having a positive refractive power and a refractive index distribution region having a negative refractive power are provided on the same axis with the center of the ring zone as an axis.
【００１２】請求項２に係る発明は、請求項１に係る固
体撮像素子用一体型集光素子において、正の屈折力を有
する屈折率分布領域の有効径が前記光電変換部の最外径
よりも大きく、かつ、少なくとも光軸近傍において前記
負の屈折力を有する屈折率分布領域の該屈折力の絶対値
が、前記正の屈折力を有する屈折率分布領域の該屈折力
の絶対値より大きいことを特徴とする。According to a second aspect of the present invention, in the solid-state imaging device integrated light-collecting element according to the first aspect, the effective diameter of the refractive index distribution region having a positive refractive power is smaller than the outermost diameter of the photoelectric conversion section. And the absolute value of the refractive power of the refractive index distribution region having the negative refractive power is greater than the absolute value of the refractive power of the refractive index distribution region having the positive refractive power at least near the optical axis. It is characterized by
【００１３】請求項３に係る発明は、請求項１または２
に記載の固体撮像素子用一体型集光素子を製造するにあ
たり、光電変換部の中心軸上の集光素子用基板の所定位
置に屈折率分布領域を形成した後、同軸上に前記屈折率
分布とは反対の屈折力を有する屈折率分布領域を積層す
ることとした。The invention according to claim 3 is the invention according to claim 1 or 2.
In manufacturing the integrated light-collecting device for a solid-state imaging device according to, after forming a refractive index distribution region at a predetermined position of the substrate for the light-collecting device on the central axis of the photoelectric conversion unit, the refractive index distribution on the same axis A refractive index distribution region having a refractive power opposite to that is laminated.
【００１４】[0014]
【作用】光電変換部が輪帯状の画素で構成される固体撮
像素子の一例における一つの画素の断面斜視図を図２に
示す。この撮像素子は、一般のフォトトランジスタと異
なり、略輪帯状のゲートを備えるＣＭＤとなっている。
受光領域に形成された多結晶シリコンゲート１を透過し
た入射光は、Ｓｉ結晶からなるｐ- 基板２上にエピタキ
シャル成長されたｎ- チャンネル層３中に正孔−電子対
を発生させる。このうち、正孔４は多結晶シリコンゲー
ト１直下の領域で、ＳｉＯ2 層５とｎ- チャンネル層３
との界面に蓄積される。すなわち、入射光の有無によ
り、多結晶シリコンゲート１の電位が変化し、ｎ+ ソー
ス層６間のチャンネルが増減し、ソース７から供給され
る電子、つまりドレイン電流が変調される。この結果、
入射光に増幅された信号電流を取り出すことができる。FIG. 2 shows a sectional perspective view of one pixel in an example of the solid-state image pickup device in which the photoelectric conversion section is composed of pixels in a ring shape. Unlike a general phototransistor, this image pickup device is a CMD having a substantially ring-shaped gate.
Incident light transmitted through the polycrystalline silicon gate 1 formed in the light receiving region generates hole-electron pairs in the n - channel layer 3 epitaxially grown on the p - substrate 2 made of Si crystal. Of these, the holes 4 are in the region immediately below the polycrystalline silicon gate 1, and the SiO 2 layer 5 and the n − channel layer 3 are formed.
Accumulates at the interface with. That is, the potential of the polycrystalline silicon gate 1 changes depending on the presence or absence of incident light, the channel between the n + source layers 6 increases and decreases, and the electrons supplied from the source 7, that is, the drain current is modulated. As a result,
The signal current amplified by the incident light can be taken out.
【００１５】このような、輪帯状の光電変換部を有した
固体撮像素子に対する集光素子の一例として、各画素毎
に図１に示すような屈折率の分布領域を形成したものが
考えられる。これは、負の屈折力を有する屈折率分布領
域９と正の屈折力を有する屈折率分布領域８とが、輪帯
状の光電変換部１０を有した固体撮像素子基板１１上に
基板側から順に積層された集光素子となっている。この
時、正の屈折力を有する屈折率分布領域８と負の屈折力
を有する屈折率分布領域９の光軸は、輪帯状の光電変部
１０の内径の中心軸上とする。また、分布の形状はパラ
ボリックであり、正の屈折率分布領域８の屈折力は負の
屈折率分布領域９の屈折力よりその絶対量で小さく、ま
た、その有効径は正の屈折率分布領域８の方が負の屈折
率分布領域９より大きいものとなっている。As an example of the light-collecting device for the solid-state image pickup device having such a ring-shaped photoelectric conversion portion, one in which a refractive index distribution region as shown in FIG. 1 is formed for each pixel is considered. This is because the refractive index distribution region 9 having a negative refractive power and the refractive index distribution region 8 having a positive refractive power are sequentially arranged from the substrate side on the solid-state image sensor substrate 11 having the annular photoelectric conversion unit 10. It is a laminated light-collecting element. At this time, the optical axes of the refractive index distribution region 8 having the positive refractive power and the refractive index distribution region 9 having the negative refractive power are on the central axis of the inner diameter of the annular photoelectric conversion portion 10. Also, the shape of the distribution is parabolic, the refractive power of the positive refractive index distribution region 8 is smaller in absolute amount than the refractive power of the negative refractive index distribution region 9, and its effective diameter is the positive refractive index distribution region. 8 is larger than the negative refractive index distribution region 9.
【００１６】これにより、各画素間の信号読みだし回路
部上の不感領域に入射する光成分は、媒質中での光線の
屈曲により、図１中のＡのような経路を通って光電変換
部１０へ集光する。また、輪帯状の光電変換部１０の内
径内部上の不感領域より入射する光成分も同様に媒質中
で屈曲し、図１中のＢのような経路を通って光電変換部
１０に集光することとなる。ここでの正の屈折力を有す
る屈折率分布領域８と負の屈折力を有する屈折率分布領
域９のぞれぞれの屈折力を制御することによって、入射
した光成分を輪帯状の光電変換部１０に効率よく集光す
ることが可能となる。As a result, the light component incident on the insensitive area on the signal reading circuit portion between each pixel passes through the path indicated by A in FIG. 1 due to the bending of the light beam in the medium, and the photoelectric conversion portion. Focus on 10. Further, the light component incident from the dead region inside the inner diameter of the ring-shaped photoelectric conversion unit 10 is similarly bent in the medium, and is condensed on the photoelectric conversion unit 10 through a path like B in FIG. It will be. By controlling the respective refractive powers of the refractive index distribution region 8 having a positive refractive power and the refractive index distribution region 9 having a negative refractive power, the incident light component is converted into a ring-shaped photoelectric conversion. It is possible to efficiently focus the light on the portion 10.
【００１７】つまり、このような集光素子を各画素上に
形成することにより、画素間および輪帯状光電変換部１
０の内径内部の不感領域に入射する光成分に対しても光
電変換部１０への集光が可能となり、固体撮像素子の高
感度化を実現することが可能となる。That is, by forming such a condensing element on each pixel, the photoelectric conversion section 1 between pixels and in the annular shape is formed.
It is possible to condense light components incident on the dead region inside the inner diameter of 0 to the photoelectric conversion unit 10, and it is possible to realize high sensitivity of the solid-state imaging device.
【００１８】また、ここでの集光素子は、あくまで光電
変換部１０に光束を集光するための素子であり、必ずし
も結像する素子である必要はないため、屈折率の分布形
状にはかなりの自由度をもたせることができる。例え
ば、分布形状は必ずしも２次の関数で表されるものであ
る必要はなく、集光に関して適当であれば、変曲点のあ
る分布や４次、６次等の高次の項で表される関数であっ
てもかまわない。また、集光素子に形成する正の屈折率
分布領域８と負の屈折率分布領域９とは画素上の所定位
置に順次積層されていればよく、どちらの屈折率分布領
域が上にあっても下にあっても本発明の作用、効果を有
するようなものであれば問題はない。Further, the condensing element here is an element for condensing the light flux on the photoelectric conversion part 10 to the last, and is not necessarily an element for forming an image. The degree of freedom of can be given. For example, the distribution shape does not necessarily have to be expressed by a quadratic function, and if appropriate for light collection, it is expressed by a distribution with an inflection point or a higher-order term such as fourth-order or sixth-order. It may be a function. Further, the positive refractive index distribution region 8 and the negative refractive index distribution region 9 formed on the light-collecting element may be sequentially laminated at predetermined positions on the pixel, and which refractive index distribution region is on top. Even if it is below, there is no problem as long as it has the action and effect of the present invention.
【００１９】これらの組み合わせを考えると図９に示す
８種が考えられ、同様の効果が得られる。Considering these combinations, eight kinds shown in FIG. 9 can be considered, and similar effects can be obtained.
【００２０】正と負の屈折力を有する屈折率分布領域に
ついて、正の負との屈折力の関係および、輪帯状の光電
変換部１０の形状を考慮したとき、本発明において、該
輪帯状の光電変換部１０の受光面積が同じであっても、
集光素子の構成を変化させることにより該輪帯状の光電
変換部１０での光量を増加させ、光感度を向上すること
ができる。そのための構成としては、 正の屈折力を有する屈折率分布領域の有効径が光電
変換部の最外径よりも大きい。 正の屈折力を有する屈折率分布領域の有効径が負の
屈折力を有する屈折率分布領域の有効径よも大きい。 負の屈折力を有する屈折率分布領域の有効径が輪帯
状の光電変換部の内径よりも小さい。 正の屈折力より負の屈折力の方が大きい。 ことのいずれかの構成が必要であり、これらの組み合わ
せであっても本発明の作用を生じる。Regarding the refractive index distribution region having positive and negative refractive powers, the relationship between the positive and negative refractive powers and the shape of the annular photoelectric conversion portion 10 are taken into consideration in the present invention. Even if the light receiving area of the photoelectric conversion unit 10 is the same,
By changing the configuration of the condensing element, it is possible to increase the amount of light in the ring-shaped photoelectric conversion unit 10 and improve the photosensitivity. As a configuration for that purpose, the effective diameter of the refractive index distribution region having a positive refractive power is larger than the outermost diameter of the photoelectric conversion section. The effective diameter of the refractive index distribution region having a positive refractive power is larger than the effective diameter of the refractive index distribution region having a negative refractive power. The effective diameter of the refractive index distribution region having negative refractive power is smaller than the inner diameter of the annular photoelectric conversion unit. Negative power is greater than positive power. Any one of these configurations is required, and even the combination thereof can produce the action of the present invention.
【００２１】すなわち、では、正の屈折力を有する屈
折率分布領域で集光された光が、光電変換部に到達し、
光量が大きくなるという作用を有し、では、正の屈折
力を有する屈折率分布領域で集光された光のうち、輪帯
状の光電変換部の中心軸付近の光線のみを負の屈折力を
有する屈折率分布領域によって発散し、光電変換部に有
効に到達させることができることにより光量を増加させ
るという作用を有し、では、負の屈折力を有する屈折
率分布領域で発散された光が輪帯状の光電変換部に有効
に到達することにより光量を増加することが可能となる
という作用を有し、では、例えば、積層の順序が正の
屈折力を有する屈折率分布領域、負の屈折力を有する屈
折率分布領域、光電変換部の順の場合、正の屈折力を有
する屈折率分布領域で集光された光を光電変換部に到達
させるため負の屈折力を有する屈折率分布領域での屈折
力を大きくし、光電変換部に到達させる光量を増大させ
ることができるという作用を有する。That is, in, the light condensed in the refractive index distribution region having a positive refractive power reaches the photoelectric conversion portion,
With the effect of increasing the amount of light, in the light condensed in the refractive index distribution region having a positive refractive power, only the light rays near the central axis of the ring-shaped photoelectric conversion unit have a negative refractive power. It has a function of increasing the amount of light by being diverged by the refractive index distribution region having, and having the effect of increasing the light amount by effectively reaching the photoelectric conversion unit. It has the effect that the amount of light can be increased by effectively reaching the strip-shaped photoelectric conversion unit. For example, in the order of stacking, a refractive index distribution region having a positive refractive power, a negative refractive power In the order of the refractive index distribution region having the, and the photoelectric conversion unit, in order to make the light condensed in the refractive index distribution region having the positive refractive power reach the photoelectric conversion unit, in the refractive index distribution region having the negative refractive power. To increase the refractive power of An effect that it is possible to increase the amount of light to reach the.
【００２２】また、〜までを組み合わせることによ
っては以下のような作用を生ずる。ととを組み合わ
せることにより、輪帯状の光電変換部の最外径よりも大
きな、正の屈折率分布領域の有効径によって、不感領域
である、輪帯状の光電変換部の外周より外側の信号の読
み出し回路上の光線を、光電変換部に集光することが可
能で、更に、負の屈折力が正の屈折力よりも大きいため
に光軸近傍では光線の発散が起こり、輪帯状の光電変換
部の内径内部上の光線を光電変換部に有効に到達するこ
とが可能となり、光量を増加するという作用を有する。
この組み合わせにおいては、輪帯状の光電変換部の内部
の光線を有効に集光させることが可能である。Further, depending on the combination of up to, the following effects occur. By combining and, by the effective diameter of the positive refractive index distribution region, which is larger than the outermost diameter of the ring-shaped photoelectric conversion unit, the dead region is a signal outside the outer periphery of the ring-shaped photoelectric conversion unit. The light beam on the readout circuit can be focused on the photoelectric conversion unit. Furthermore, since the negative refracting power is larger than the positive refracting power, the light beam diverges near the optical axis, resulting in a ring-shaped photoelectric conversion. The light rays inside the inner diameter of the section can effectively reach the photoelectric conversion section, which has the effect of increasing the light amount.
With this combination, it is possible to effectively collect the light rays inside the annular photoelectric conversion unit.
【００２３】さらに、ととの組み合わせで、が光
電変換部の中心軸上の光軸近傍で構成されておれば、輪
帯状の光電変換部の最外径よりも大きな有効径を有し、
正の屈折力を有する屈折率分布領域によって、不感領域
である、輪帯状の光電変換部の外周より外側の信号の読
み出し回路上の光線を、より多く光電変換部に集光する
ことが可能である。更に、少なくとも光軸近傍で負の屈
折力が正の屈折力よりも大きいために光線の発散が起こ
り、輪帯状の光電変換部の内径内部上の光線をより多く
光電変換部に有効に到達することが可能となり、光量を
増加するという作用を有する。少なくとも光軸近傍の負
の屈折力を有する屈折率分布領域の該屈折力が、正の屈
折力を有する屈折率分布領域の該屈折力よりも大きけれ
ばよく、分布形状の変化を方向に対し、パラボリックで
ないものであっても適応できる。分布の形状を考慮すれ
ば負の屈折力を有する屈折率分布領域を正の屈折力を有
する屈折率分布領域に対して有効径で小さく設定する必
要はなく作製上の自由度が増す。Further, in combination with and, if is formed in the vicinity of the optical axis on the central axis of the photoelectric conversion part, it has an effective diameter larger than the outermost diameter of the annular photoelectric conversion part,
With the refractive index distribution region having a positive refractive power, it is possible to collect more light rays on the readout circuit of the signal outside the outer periphery of the ring-shaped photoelectric conversion unit, which is a dead region, on the photoelectric conversion unit. is there. Further, since the negative refracting power is larger than the positive refracting power at least near the optical axis, divergence of light rays occurs, and more light rays inside the inner diameter of the ring-shaped photoelectric conversion portion effectively reach the photoelectric conversion portion. This makes it possible to increase the amount of light. At least the refractive power of the refractive index distribution region having a negative refractive power in the vicinity of the optical axis is greater than the refractive power of the refractive index distribution region having a positive refractive power, the change of the distribution shape with respect to the direction, It can be applied even if it is not parabolic. Considering the shape of the distribution, it is not necessary to set the refractive index distribution region having a negative refractive power smaller than the refractive index distribution region having a positive refractive power with an effective diameter, and the degree of freedom in manufacturing increases.
【００２４】ととを組み合わせることにより、負の
屈折力を有する屈折率分布領域の該屈折力が、正の屈折
力を有する屈折率分布領域の該屈折力よりも大きいた
め、一旦、正の屈折力により集光された光線を完全に発
散させ光電変換部に集光させることが可能であり、か
つ、負の屈折力を有する屈折率分布領域の有効径が光電
変換部の内径内部に対して小さいものであるため内径内
部上の光線のみを光電変換部に向けて発散することが可
能であり、光電変換部上の光線を発散してしまうことが
なく、光量の増加に有効的である。この組み合わせにお
いては、特に内径内部上の光線を確実に光電変換部に集
光させることが可能である。By combining and, since the refractive power of the refractive index distribution region having the negative refractive power is larger than the refractive power of the refractive index distribution region having the positive refractive power, once the positive refractive power It is possible to completely diverge the light beam condensed by the force and condense it to the photoelectric conversion part, and the effective diameter of the refractive index distribution region having negative refractive power is inside the inner diameter of the photoelectric conversion part. Since it is small, only the light rays inside the inner diameter can be diverged toward the photoelectric conversion portion, and the light rays on the photoelectric conversion portion are not diverged, which is effective in increasing the light amount. With this combination, it is possible to surely focus the light rays on the inside of the inner diameter on the photoelectric conversion portion.
【００２５】ととを組み合わせことにより、輪帯状
の光電変換部の最外径よりも大きな、正の屈折力を有す
る屈折率分布領域の有効径によって、不感領域である輪
帯状の光電変換部の外周より外側の信号の読み出し回路
上の光線を、光電変換部に集光することが可能で、更
に、負の屈折力を有する屈折率分布領域の有効径が、輪
帯状の光電変換部の内径内部よりも小さい構成となって
いるため、輪帯状の光電変換部の内径内部上の光線のみ
を光電変換部に有効に到達さることが可能となり、光量
を増加させるという作用を有する。この組み合わせにお
いては、特に輪帯状の光電変換部の光電変換部の内外の
光線を有効に集光させることが可能となる。By combining and, the effective diameter of the refractive index distribution region having a positive refractive power, which is larger than the outermost diameter of the ring-shaped photoelectric conversion unit, allows the ring-shaped photoelectric conversion unit which is a dead region to be formed. Light rays on the readout circuit for signals outside the outer circumference can be focused on the photoelectric conversion unit, and the effective diameter of the refractive index distribution region having negative refractive power is the inner diameter of the annular photoelectric conversion unit. Since the structure is smaller than the inside, only the light rays inside the inner diameter of the ring-shaped photoelectric conversion portion can effectively reach the photoelectric conversion portion, and the light amount is increased. In this combination, it is possible to effectively focus the light rays inside and outside the photoelectric conversion portion of the annular photoelectric conversion portion.
【００２６】とととを組み合わせることにより、
ととを組み合わせることにより生じる、内径内部に
対する光線を効率よく光電変換部に集光することが可能
になる他、光電変換部の外径より外側の信号読み出し回
路上の光線を集光させることが可能となり、輪帯状の光
電変換部の内外の光線をさらに効率よく集光することが
可能となる。By combining and with
It is possible to efficiently collect the light rays to the inside of the inner diameter, which are generated by combining and, and also to collect the light rays on the signal reading circuit outside the outer diameter of the photoelectric conversion section. This makes it possible to more efficiently collect the light rays inside and outside the ring-shaped photoelectric conversion unit.
【００２７】以下に、前述した正の屈折率分布領域８と
負の屈折率分布領域９を組み合わせたマイクロレンズ
（図１）の製造方法の一例について図３に基づき説明す
る。ここでは、屈折率を増大する能力を、金属成分Ａ＞
金属成分Ｂ＞金属成分Ｃとする。まず、シリコンのアル
コキシド等を主成分とし金属成分Ｂを含有するゾルを調
製し、固体撮像素子基板１１上にコートしてゲル化させ
ることにより、第１層１２を形成する。その後、第１層
１２上の所定の位置にマスク１３を形成し、それを金属
成分Ｃを含有するアルコール溶液中に浸漬し、マスキン
グによる露出部を介し金属成分Ｂと金属成分Ｃを交換し
て屈折率の分布を形成する。この工程により分布の中心
の屈折率が最も低く（金属成分Ｃの濃度が高い）、中心
から半球状に徐々に屈折率の高くなる（金属成分Ｂの濃
度が高い）負の屈折力の屈折率分布領域９となる。ここ
で、一旦マスキングを除去し、熱処理を行なうことによ
ってゲルを緻密化させる。An example of a method of manufacturing the microlens (FIG. 1) in which the positive refractive index distribution region 8 and the negative refractive index distribution region 9 described above are combined will be described below with reference to FIG. Here, the metal component A>
Metal component B> metal component C. First, a sol containing a silicon alkoxide as a main component and a metal component B is prepared, and the first layer 12 is formed by coating on the solid-state imaging element substrate 11 and gelling. After that, a mask 13 is formed at a predetermined position on the first layer 12, the mask 13 is immersed in an alcohol solution containing the metal component C, and the metal component B and the metal component C are exchanged through the exposed portion by masking. Form a refractive index distribution. By this step, the refractive index at the center of the distribution is the lowest (the concentration of the metal component C is high), and the refractive index gradually increases from the center to the hemisphere (the concentration of the metal component B is high). It becomes the distribution area 9. Here, the gel is densified by once removing the masking and performing heat treatment.
【００２８】次に、前記ゾルと同組成のゾルを再度第１
層１２上にコートし、ゲル化させることにより、第２層
１４を形成する。そして、この第２層１４上に前記屈折
率分布領域９の光軸上の点が露出するようにマスキング
を行なう。この固体撮像素子基板１１を更に金属成分Ａ
を含有するアルコール溶液中に浸漬し、露出部を介し金
属成分Ａと金属成分Ｂの交換を行なう。この交換によっ
て、表面層の分布中心部で屈折率が最も高く（金属成分
Ａの濃度が高い）、中心から半球状に屈折率が徐々に減
少する（金属成分Ｂの濃度が高い）正の屈折力を有す屈
折率分布領域８が形成される。これにより、図１に示す
ような集光素子を作製することが可能となる。Next, a sol having the same composition as the sol is first re-applied.
The second layer 14 is formed by coating on the layer 12 and gelling. Then, masking is performed on the second layer 14 so that the points on the optical axis of the refractive index distribution region 9 are exposed. This solid-state image pickup device substrate 11 is further treated with a metal component A.
The metal component A and the metal component B are exchanged through the exposed portion by immersing in an alcohol solution containing. By this exchange, the refractive index is highest in the center of the distribution of the surface layer (the concentration of the metal component A is high), and the refractive index gradually decreases from the center to a hemisphere (the concentration of the metal component B is high). A refractive index distribution region 8 having a force is formed. As a result, it becomes possible to manufacture the light-collecting device as shown in FIG.
【００２９】この方法によれば、分布形成の際に、固体
撮像素子基板上から光電変換部までの距離や、輪帯の大
きさ等を考慮して、金属種やゲル中の金属含有率、分布
液中の濃度、温度、分布時間等のパラメータを制御する
ことにより、集光の程度を制御した分布を作製すること
ができ、輪帯状に集光させるために都合のよい条件を選
択することができる。According to this method, in forming the distribution, the metal content in the metal species in the gel and the metal content in the gel, considering the distance from the solid-state image pickup device substrate to the photoelectric conversion part, the size of the ring zone, etc. By controlling parameters such as concentration in distribution liquid, temperature, distribution time, etc., it is possible to create a distribution in which the degree of light collection is controlled, and select a condition that is convenient for collecting light in an annular shape. You can
【００３０】ここでの、屈折率の分布の形成は、拡散現
象を利用し、含有する金属成分を交換・溶出することに
より行なうものであり、ガラスを溶融塩中に浸漬するイ
オン交換法で行なっても良いし、また、金属アルコキシ
ドを原料とするゾルをゲル化させた後、金属成分を酸で
溶出したり、アルコール等の溶媒中で他の金属種と交換
するゾル・ゲル法で行なってもかまわない。また、その
用途によっては、ＣＶＤ法等により作製したスートや、
分相させたアルカリボロシリケートガラスの酸処理によ
って作製した多孔質ガラス等に対して分布の付与を行な
ってもよい。しかし、集光作用の他、色収差の補正等を
考慮すると、２価以上の金属成分に分布付与が可能であ
るゾル・ゲル法が、金属種の制限が少ないために効果的
である。The formation of the refractive index distribution here is carried out by exchanging and eluting the metal components contained therein by utilizing a diffusion phenomenon, and is carried out by an ion exchange method in which glass is immersed in a molten salt. Alternatively, the sol-gel method in which the sol made from the metal alkoxide is gelled, and then the metal component is eluted with an acid or exchanged with another metal species in a solvent such as alcohol is carried out. I don't care. Also, depending on the application, soot made by the CVD method,
Distribution may be imparted to the porous glass or the like prepared by acid treatment of the phase-separated alkali borosilicate glass. However, in consideration of correction of chromatic aberration and the like in addition to the light condensing action, the sol-gel method, which is capable of giving distribution to bivalent or higher valent metal components, is effective because there are few restrictions on the metal species.
【００３１】また、屈折率分布領域を形成する場合、そ
の分布は、画素上に積層されたもので輪帯状光電変換部
の軸と同軸上であれば、表面部に向い分布しているもの
であっても、画素側に分布しているものであってもかま
わない。また、屈折率分布はここで示した球面分布以外
に径方向分布であっても問題ない。その作製の方法とし
てそれぞれの屈折力領域は単独に作製し、積層する方法
や、基板の両面から同時に作製する方法を用いることが
できる。In the case where the refractive index distribution region is formed, the distribution is such that it is laminated on the pixel and is distributed toward the surface portion if it is coaxial with the axis of the annular photoelectric conversion portion. It does not matter even if they are distributed on the pixel side. Further, the refractive index distribution may be a radial distribution other than the spherical distribution shown here, and there is no problem. As a method for producing the same, it is possible to use a method of producing each refractive power region independently and laminating it, or a method of simultaneously producing from both sides of the substrate.
【００３２】[0032]
【実施例１】図１に示すように、本実施例は各画素上の
光電変換部１０の中心軸と同軸上に２つの屈折率分布領
域８，９を形成した例である。この例では、画素側から
順に負の球面屈折率分布領域９、正の球面屈折率分布領
域８を積層した構成であり、分布の中心部は両者とも表
面側となっている。ここで画素上の集光素子中心部付近
を透過する光線は、図１中のＡのように屈曲し輪帯状の
光電変換部１０上に集光する。また、集光素子の外周部
付近を透過する光線は、図１中のＢのような経路で屈曲
し輪帯状の光電変換部１０上に集光する。この集光素子
を輪帯状の光電変換部１０を有する固体撮像素子の集光
素子として用いたところ、集光効率が著しく向上した。Embodiment 1 As shown in FIG. 1, this embodiment is an example in which two refractive index distribution regions 8 and 9 are formed coaxially with the central axis of the photoelectric conversion portion 10 on each pixel. In this example, a negative spherical refractive index distribution region 9 and a positive spherical refractive index distribution region 8 are laminated in this order from the pixel side, and the central portion of the distribution is on the surface side. Here, the light ray that passes through the vicinity of the central portion of the light-collecting element on the pixel is bent as shown by A in FIG. 1 and is condensed on the ring-shaped photoelectric conversion portion 10. Further, a light ray that passes through the vicinity of the outer peripheral portion of the light-collecting element is bent on a path such as B in FIG. 1 and is condensed on the ring-shaped photoelectric conversion unit 10. When this light-collecting device was used as a light-collecting device for a solid-state imaging device having a ring-shaped photoelectric conversion unit 10, the light-collecting efficiency was significantly improved.
【００３３】[0033]
【実施例２】実施例１に示した集光素子（図１）の作製
法の一例について説明する。ここで、各金属成分の屈折
率に対する影響は、鉛＞バリウム＞カリウムの順であ
る。シリコンのメトキシドと酢酸バリウムを原料とする
ゾルを調製し、固体撮像素子基板上にコートしてゲル化
させ、第１層を形成する。この第１層上の所定の位置を
露出させたマスクを形成した後、これを酢酸カリウムを
含有するエタノール溶液中に浸漬し、バリウムとカリウ
ムの交換を行って屈折率の分布を形成した。この段階で
の屈折率の分布は、分布の中心の屈折率が最も低く分布
中心から半球状に徐々に屈折率が高くなる負の屈折力の
屈折率分布領域となる。ここで、一旦マスキングを除去
し、熱処理を行なうことによってゲルを緻密化させた。[Embodiment 2] An example of a method for manufacturing the light-collecting device (FIG. 1) shown in Embodiment 1 will be described. Here, the influence of each metal component on the refractive index is in the order of lead>barium> potassium. A sol using silicon methoxide and barium acetate as raw materials is prepared, coated on a solid-state imaging device substrate and gelated to form a first layer. After forming a mask exposing a predetermined position on the first layer, the mask was immersed in an ethanol solution containing potassium acetate, and barium and potassium were exchanged to form a refractive index distribution. The distribution of the refractive index at this stage is a refractive index distribution region of negative refractive power in which the refractive index at the center of the distribution is lowest and the refractive index gradually increases from the distribution center to a hemisphere. Here, the mask was once removed and heat treatment was performed to densify the gel.
【００３４】次に、前記ゾルと同組成のシリコンメトキ
シドおよび酢酸バリウムからなるゾルを再度第１層上に
コートし、ゲル化させた。このゲル上に前記屈折率分布
領域の軸上の点が露出するようにマスキングを行なっ
た。これを更に酢酸鉛を含有するエタノール溶液中に浸
漬し、鉛とバリウムの交換を行なった。この交換によっ
て分布の中心部で屈折率が最も高く、中心から半球状に
屈折率が徐々に減少する正の屈折力を有す屈折率分布領
域が、前述の負の屈折力領域上に形成した。この固体撮
像素子基板のマスキングを除去し、再度熱処理を行なう
ことによってゲルを緻密化させた。得られた集光素子を
輪帯状の光電変換部を有する固体撮像素子として使用し
たところ、小型にして感度の向上が確認できた。Next, a sol composed of silicon methoxide and barium acetate having the same composition as the sol was coated again on the first layer to cause gelation. Masking was performed on this gel so that the points on the axis of the refractive index distribution region were exposed. This was further immersed in an ethanol solution containing lead acetate to exchange lead and barium. Due to this exchange, the refractive index distribution region having the highest refractive index in the central part of the distribution and the positive refractive power in which the refractive index gradually decreases from the center to the hemisphere is formed on the above-mentioned negative refractive power region. . The mask was removed from the solid-state imaging device substrate, and heat treatment was performed again to densify the gel. When the obtained light-collecting device was used as a solid-state image pickup device having a ring-shaped photoelectric conversion portion, it was confirmed that the size was reduced and the sensitivity was improved.
【００３５】[0035]
【実施例３】図４に実施例３の集光素子の構成を示す。
これは、屈折率の分布領域が画素側から正の屈折力の屈
折率分布領域８、負の屈折力の屈折率分布領域９となっ
たものであり、前述と同様に、入射する光線は図４中の
Ａ、Ｂのような経路を通り光電変換部１０に集光する。
この集光素子を固体撮像素子用の一体型集光素子として
使用したところ、小型にして高感度化が実現した。[Third Embodiment] FIG. 4 shows the structure of a light-collecting device according to a third embodiment.
This is because the refractive index distribution area is a refractive index distribution area 8 of positive refractive power and a refractive index distribution area 9 of negative refractive power from the pixel side. The light is condensed on the photoelectric conversion unit 10 through the paths A and B in FIG.
When this condensing element was used as an integrated condensing element for a solid-state image pickup element, it was downsized and high sensitivity was realized.
【００３６】[0036]
【実施例４】図５に本実施例の集光素子の構成を示す。
これは、屈折力を有する領域が画素側からそれぞれ負の
屈折率分布領域９、正の屈折率分布領域８となっている
集光素子であり、その分布形状のうち正の屈折力を有す
る屈折率分布領域８の分布形状は図６（ａ）に示すよう
なパラボリックであるが、負の屈折力を有する屈折率分
布領域９ではパラボリックではなく、図６（ｂ）に示す
ような分布となっている。また、正の屈折力を有する屈
折率分布領域の有効径が輪帯状の光電変換部の最外径よ
りも大きい構成となっている。この例においては、正の
屈折率分布領域８と負の屈折率分布領域９の深さ方向の
大きさは等しいが、負の屈折率分布領域９における屈折
力が中心部で大きく、外周部に向かうに従って次第に小
さくなっている。これにより、外周部の光線は、Ａのよ
うに正の屈折率分布領域８で内側に屈曲した光線が負の
屈折率分布領域９では分布中心からはなれた分布の勾配
の小さな部分を通るため、負の屈折力の影響をあまり受
けずに光電変換部１０に集光する。また、中心部付近を
通る光線は、Ｂのように正の屈折率分布領域８で一旦内
側に集光されるが、負の屈折率分布領域９で中心部付近
の勾配の大きな部分を通るために、外側に発散されて光
電変換部１０に集光することとなる。この集光素子を固
体撮像素子用の一体型集光素子として使用したところ、
小型にして高感度化が実現した。[Embodiment 4] FIG. 5 shows the structure of a light-collecting device of this embodiment.
This is a light-collecting element in which regions having a refractive power are a negative refractive index distribution region 9 and a positive refractive index distribution region 8 from the pixel side, respectively. The distribution shape of the index distribution region 8 is parabolic as shown in FIG. 6 (a), but the refractive index distribution region 9 having a negative refractive power is not parabolic and has a distribution as shown in FIG. 6 (b). ing. Further, the effective diameter of the refractive index distribution region having a positive refractive power is larger than the outermost diameter of the annular photoelectric conversion portion. In this example, the positive refractive index distribution region 8 and the negative refractive index distribution region 9 have the same size in the depth direction, but the refractive power in the negative refractive index distribution region 9 is large in the central portion and is large in the outer peripheral portion. It is getting smaller as you go. As a result, as for the light rays in the outer peripheral portion, the light rays bent inward in the positive refractive index distribution area 8 as in A, pass through the negative refractive index distribution area 9 passing through a portion having a small distribution gradient away from the distribution center. The light is focused on the photoelectric conversion unit 10 without being significantly affected by the negative refractive power. Further, a light ray passing near the central portion is once focused inward in the positive refractive index distribution region 8 as in B, but it passes through a portion having a large gradient near the central portion in the negative refractive index distribution region 9. Then, the light is diverged to the outside and condensed on the photoelectric conversion unit 10. When this condensing element was used as an integrated condensing element for a solid-state image sensor,
Compact size and high sensitivity have been realized.
【００３７】[0037]
【実施例５】図７に従い、本実施例の集光素子の作製方
法について説明する。これは、正の屈折率分布領域８と
負の屈折率分布領域９が積層された集光素子である。シ
リコンエトキシドと酢酸カリウムを原料とするゾルを固
体撮像素子基板１１上にゾルの表面張力を利用しマトリ
ックス状に液滴を形成してゲル化させ、マトリックス状
のレンズ１５を形成した。これを酢酸バリウムのエタノ
ール溶液１６中に浸漬して、カリウムとバリウムの交換
を行ない、分布を形成した。ここに、シリコンのエトキ
シドと酢酸バリウムを原料とするゾルを塗布しゲル化さ
せた（ゲル層１７）。さらにこのゲル層１７上にマスク
キング処理を施し、液滴状のレンズ上の点を露出させ
た。これを、酢酸鉛を溶解させたエタノール溶液中に浸
漬し、バリウムと鉛の交換を行なった。マスク１３を除
去後、熱処理を行ない緻密化することで、図７に示すよ
うな屈折率分布を有する集光素子を作製した。この集光
素子を固体撮像素子用一体型集光素子として利用したと
ころ、小型にして高感度化が実現した。[Embodiment 5] A method of manufacturing the light-collecting device of this embodiment will be described with reference to FIG. This is a light-collecting element in which a positive refractive index distribution region 8 and a negative refractive index distribution region 9 are stacked. A sol made of silicon ethoxide and potassium acetate was formed on the solid-state image pickup device substrate 11 using the surface tension of the sol to form droplets in a matrix form and gelled to form a matrix lens 15. This was immersed in an ethanol solution 16 of barium acetate, and potassium and barium were exchanged to form a distribution. A sol made of silicon ethoxide and barium acetate as a raw material was applied and gelated (gel layer 17). Further, masking treatment was performed on the gel layer 17 to expose the droplet-shaped points on the lens. This was immersed in an ethanol solution in which lead acetate was dissolved, and barium and lead were exchanged. After removing the mask 13, heat treatment was performed for densification to manufacture a light-collecting element having a refractive index distribution as shown in FIG. 7. When this light-collecting device was used as an integrated light-collecting device for a solid-state image sensor, it was downsized and high sensitivity was realized.
【００３８】[0038]
【実施例６】図８に本実施例の集光素子の製造方法を示
す。ゾル・ゲル法によりシリコンメトキシドと硝酸バリ
ウムを原料とする板状でゲル状の集光素子用基板１８を
作製した。この集光素子用基板１８の両面の所定の位置
を露出させたマスキング処理を行ない、これを浸漬容器
１９中に集光素子用基板１８が仕切りとなるように立
て、その両側を異なる金属塩を含有する２種の溶液２
０，２１で満たした。このときの２種の金属塩として片
側には０．１ｍｏｌ／ｌの酢酸鉛のエタノール溶液２０
を、他方には０．０１ｍｏｌ／ｌの酢酸ナトリウムのエ
タノール溶液２１を用いた。このとき、バリウム−鉛、
バリウム−ナトリウムの交換速度の差により、屈折率分
布領域の有効径は正の屈折率分布領域の有効径が大き
く、負の屈折率分布領域が小さいものとなった。また、
両者の屈折率分布はパラボリックなものであった。この
ようにして得られた集光素子用基板１８を緻密化し、輪
帯状の光電変換部を有する固体撮像素子用の集光素子と
して用いたところ、小型にして高感度化が実現した。Sixth Embodiment FIG. 8 shows a method of manufacturing the light-collecting device of this embodiment. A plate-like condensing element substrate 18 made of silicon methoxide and barium nitrate was prepared by the sol-gel method. A masking process is performed by exposing predetermined positions on both surfaces of the light-collecting element substrate 18, and the light-collecting element substrate 18 is erected in a dipping container 19 so as to serve as a partition. Two kinds of solution containing 2
Filled with 0,21. At this time, 0.1 mol / l of lead acetate in ethanol solution 20 as two kinds of metal salts was used on one side.
On the other hand, 0.01 mol / l sodium acetate ethanol solution 21 was used. At this time, barium-lead,
Due to the difference in barium-sodium exchange rate, the effective diameter of the refractive index distribution region was large in the positive refractive index distribution region and small in the negative refractive index distribution region. Also,
Both refractive index distributions were parabolic. The condensing element substrate 18 obtained in this manner was densified and used as a condensing element for a solid-state imaging device having a ring-shaped photoelectric conversion section, and it was downsized and high sensitivity was realized.
【００３９】なお、請求項１記載の固体撮像素子用一体
型集光素子において、前記正の屈折力を有する屈折率分
布領域の有効径を前記光電変換部の最外径よりも大きく
してもよい。In the integrated light-collecting device for a solid-state image pickup device according to claim 1, even if the effective diameter of the refractive index distribution region having the positive refractive power is larger than the outermost diameter of the photoelectric conversion portion. Good.
【００４０】また、上記請求項１記載の集光素子におい
て、前記負の屈折力を有する屈折率分布領域の該屈折力
の絶対値を、前記正の屈折力を有する屈折率分布領域の
該屈折力の絶対値より大きくしてもよい。Further, in the light-collecting device according to claim 1, the absolute value of the refractive power of the refractive index distribution region having the negative refractive power is set to the refractive index of the refractive index distribution region having the positive refractive power. It may be larger than the absolute value of force.
【００４１】上記請求項１記載の集光素子において、前
記負の屈折力を有する屈折率分布領域の有効径を前記光
電変換部の内径よりも小さくしてもよい。In the light-collecting device according to the first aspect, the effective diameter of the refractive index distribution region having the negative refractive power may be smaller than the inner diameter of the photoelectric conversion section.
【００４２】上記請求項１記載の集光素子において、前
記正の屈折力を有する屈折率分布領域の有効径を前記光
電変換部の最外径よりも大きく、かつ、前記負の屈折力
を有する屈折率分布領域の該屈折力の絶対値を、前記正
の屈折力を有する屈折率分布領域の該屈折力の絶対値よ
り大きくしてもよい。In the light-collecting device according to claim 1, the effective diameter of the refractive index distribution region having the positive refractive power is larger than the outermost diameter of the photoelectric conversion portion, and the negative refractive power is provided. The absolute value of the refractive power of the refractive index distribution region may be larger than the absolute value of the refractive power of the refractive index distribution region having the positive refractive power.
【００４３】上記請求項１記載の集光素子において、前
記負の屈折力を有する屈折率分布領域の該屈折力の絶対
値を、前記正の屈折力を有する屈折率分布領域の該屈折
力の絶対値より大きく、かつ、前記負の屈折力を有する
屈折率分布領域の有効径を前記光電変換部の内径よりも
小さくしてもよい。In the condensing element according to claim 1, the absolute value of the refractive power of the refractive index distribution region having the negative refractive power is set to the absolute value of the refractive power of the refractive index distribution region having the positive refractive power. The effective diameter of the refractive index distribution region having a negative refractive power, which is larger than the absolute value, may be smaller than the inner diameter of the photoelectric conversion unit.
【００４４】上記請求項１記載の集光素子において、前
記正の屈折力を有する屈折率分布領域の有効径を前記光
電変換部の最外径よりも大きく、かつ、前記負の屈折力
を有する屈折率分布領域の有効径を前記光電変換部の内
径よりも小さくしてもよい。In the condensing element according to claim 1, the effective diameter of the refractive index distribution region having the positive refractive power is larger than the outermost diameter of the photoelectric conversion portion, and the negative refractive power is provided. The effective diameter of the refractive index distribution region may be smaller than the inner diameter of the photoelectric conversion section.
【００４５】上記請求項１記載の集光素子において、前
記正の屈折力を有する屈折率分布領域の有効径を前記光
電変換部の最外径よりも大きく、かつ、前記負の屈折力
を有する屈折率分布領域の有効径を前記光電変換部の内
径よりも小さく、かつ、前記負の屈折力を有する屈折率
分布領域の該屈折力の絶対値を、前記正の屈折力を有す
る屈折率分布領域の該屈折力の絶対値より大きくしても
よい。In the light-collecting device according to claim 1, the effective diameter of the refractive index distribution region having the positive refractive power is larger than the outermost diameter of the photoelectric conversion portion, and the negative refractive power is provided. The effective diameter of the refractive index distribution region is smaller than the inner diameter of the photoelectric conversion portion, and the absolute value of the refractive power of the refractive index distribution region having the negative refractive power is the refractive index distribution having the positive refractive power. It may be larger than the absolute value of the refractive power of the region.
【００４６】上記請求項１記載の集光素子において、正
の屈折率分布領域の有効径を負の屈折率分布の有効径よ
り大きく、また、前記正の屈折力を有する屈折率分布領
域の有効径を前記光電変換部の最外径よりも大きく、か
つ、前記負の屈折力を有する屈折率分布領域の有効径よ
りも大きく、かつ、前記負の屈折力を有する屈折率分布
領域の有効径を前記光電変換部変換部の内径よりも小さ
く、かつ、前記負の屈折力を有する屈折率分布領域の該
屈折力の絶対値を、前記正の屈折力を有する屈折率分布
領域の該屈折力の絶対値より大きくしてもよい。In the condensing element according to claim 1, the effective diameter of the positive refractive index distribution region is larger than the effective diameter of the negative refractive index distribution, and the effective diameter of the refractive index distribution region having the positive refractive power is effective. The diameter is larger than the outermost diameter of the photoelectric conversion part, and is larger than the effective diameter of the refractive index distribution region having the negative refractive power, and the effective diameter of the refractive index distribution region having the negative refractive power. Is smaller than the inner diameter of the photoelectric conversion unit conversion unit, and the absolute value of the refractive power of the refractive index distribution region having the negative refractive power, the refractive power of the refractive index distribution region having the positive refractive power May be larger than the absolute value of.
【００４７】なお、本発明（請求項１〜３および上記各
変形例を含む）において、固体撮像素子用一体型集光素
子を製造するにあたり、光電変換部の中心軸上に集光素
子用基板の所定位置に屈折率分布領域を形成した後、同
軸上に前記屈折率分布とは反対の屈折力を有する屈折率
分布領域を積層するとよい。In the present invention (including claims 1 to 3 and each of the above modifications), when manufacturing the integrated light-collecting device for a solid-state image pickup device, the light-collecting device substrate is placed on the central axis of the photoelectric conversion section. After the refractive index distribution region is formed at a predetermined position, a refractive index distribution region having a refractive power opposite to that of the refractive index distribution may be coaxially laminated.
【００４８】また、ゾル・ゲル法により、シリコン以外
の少なくとも一種の金属成分を含有するゾルを、固体撮
像素子基板に塗布し、ゲル化した後、マスキング処理を
施し、露呈部を介して、前記シリコン以外の少なくとも
一種の金属成分とは異なる種類の金属成分を含有する分
布付与液と接触させることにより金属成分の交換を行な
う固体撮像素子用一体型集光素子の製造方法が、固体撮
像素子の小型化および感度向上を図るのに有効である。Further, by a sol-gel method, a sol containing at least one kind of metal component other than silicon is applied to a solid-state image pickup device substrate, gelled, and then masked, and then exposed through the exposed portion. A method for manufacturing an integrated light-collecting device for a solid-state image sensor, comprising exchanging metal components by contacting a distribution-imparting liquid containing a metal component different from at least one metal component other than silicon, This is effective for downsizing and improving sensitivity.
【００４９】また、ゾル・ゲル法により、シリコン以外
の少なくとも一種の金属成分を含有するゾルをゲル化し
た後、このゲル状の集光素子用基板の両面の所定位置に
マスキング処理を施し、露呈部を介して、前記シリコン
以外の少なくとも一種の金属成分とは異なる種類の金属
成分を含有する分布付与液と接触させ金属成分の交換を
行なう工程において、一方の面と接触させる分布付与液
中の金属成分が集光素子用基板に含有させた金属成分よ
り屈折率に対する寄与が大きく、他方の面と接触させる
分布付与液中の金属成分が集光素子用基板に含有させた
金属成分より屈折率に対する寄与が小さいものであると
する固体撮像素子用一体型集光素子の製造方法も、固体
撮像素子の小型化および感度向上を図るのに適した製造
方法である。Further, after the sol containing at least one kind of metal component other than silicon is gelated by the sol-gel method, masking treatment is applied to predetermined positions on both surfaces of the gel light-condensing element substrate to expose it. In the distribution-imparting liquid to be brought into contact with one surface in the step of contacting with a distribution-imparting liquid containing a metal component of a kind different from at least one metal component other than silicon through the part to exchange the metal component. The metal component has a larger contribution to the refractive index than the metal component contained in the light-collecting element substrate, and the metal component in the distribution-imparting liquid that comes into contact with the other surface has a higher refractive index than the metal component contained in the light-collecting element substrate. The method for manufacturing the integrated light-collecting device for a solid-state imaging device, which is considered to have a small contribution to the above, is also a manufacturing method suitable for downsizing the solid-state imaging device and improving sensitivity.
【００５０】なお、屈折率に対する寄与の大きさは、ガ
ラスの物性における加成性から考えられるもので、アッ
ペンらによる屈折率の加成性因子の値（Ａ．Ａ．アッペ
ン著ガラスの化学 日ソ通信社）が大きいものが屈折率
に対する寄与の大きい金属種である。The magnitude of the contribution to the refractive index is considered from the additive property in the physical properties of glass, and the value of the additive factor of the refractive index by Appen et al. The ones that have a large contribution to the refractive index are the metal species that make a large contribution to the refractive index.
【００５１】[0051]
【発明の効果】以上のように、請求項１〜３に係る発明
によれば、輪帯状の光電変換部を有する固体撮像素子上
の不感領域に入射する光を光電変換部に効率よく集光す
ることができ、これにより、固体撮像素子の画素の微細
化による素子の小型化と高感度化を同時に達成すること
が可能となる。As described above, according to the inventions of claims 1 to 3, the light incident on the insensitive region on the solid-state image pickup device having the ring-shaped photoelectric conversion portion is efficiently condensed on the photoelectric conversion portion. Therefore, it is possible to achieve miniaturization of the element and high sensitivity at the same time by miniaturizing the pixel of the solid-state imaging element.
【図面の簡単な説明】[Brief description of drawings]
【図１】実施例１の集光素子の光路を示す光路図であ
る。FIG. 1 is an optical path diagram showing an optical path of a condensing element of Example 1.
【図２】画素の光電変換部の形状が略輪帯状である固体
撮像素子の断面斜視図である。FIG. 2 is a cross-sectional perspective view of a solid-state image sensor in which a photoelectric conversion unit of a pixel has a substantially annular shape.
【図３】本発明による集光素子の作製工程を示す工程図
である。FIG. 3 is a process drawing showing a process of manufacturing a light-collecting device according to the present invention.
【図４】実施例３の集光素子の光路を示す光路図であ
る。FIG. 4 is an optical path diagram showing an optical path of a condensing element of Example 3.
【図５】実施例４の集光素子の光路を示す光路図であ
る。FIG. 5 is an optical path diagram showing an optical path of a condensing element of Example 4.
【図６】実施例４の集光素子の正の屈折率分布形状を示
すグラフ（ａ）、負の屈折率分布形状を示すグラフ
（ｂ）である。6A and 6B are a graph (a) showing a positive refractive index distribution shape and a graph (b) showing a negative refractive index distribution shape of the light collecting element of Example 4.
【図７】実施例５の集光素子の作製工程を示す工程図で
ある。7A to 7C are process drawings showing a manufacturing process of the light-collecting device of Example 5;
【図８】実施例６の集光素子の作製装置を示す断面図で
ある。FIG. 8 is a cross-sectional view showing an apparatus for manufacturing a light-collecting device of Example 6.
【図９】本発明の正負組み合わせ変形例を示す図であ
る。FIG. 9 is a diagram showing a positive / negative combination modification example of the present invention.
１ 多結晶シリコンゲート ２ ｐ- 基板 ３ ｎ- チャンネル層 ４ 正孔 ５ ＳｉＯ2 層 ６ ｎ+ ソース層 ７ ソース ８ 正の屈折率分布領域 ９ 負の屈折率分布領域 １０ 光電変換部 １１ 固体撮像素子基板 １２ 第１層 １３ マスク １４ 第２層 １５ レンズ １６ 酢酸バリウムのエタノール溶液 １７ ゲル層 １８ 集光素子用基板 ２０ 酢酸鉛のエタノール溶液 ２１ 酢酸ナトリウムのエタノール溶液DESCRIPTION OF SYMBOLS 1 Polycrystalline silicon gate 2 p - Substrate 3 n - Channel layer 4 Holes 5 SiO 2 layer 6 n + Source layer 7 Source 8 Positive refractive index distribution region 9 Negative refractive index distribution region 10 Photoelectric conversion unit 11 Solid-state image sensor Substrate 12 First Layer 13 Mask 14 Second Layer 15 Lens 16 Barium Acetate Ethanol Solution 17 Gel Layer 18 Condenser Element Substrate 20 Lead Acetate Ethanol Solution 21 Sodium Acetate Ethanol Solution
Claims (3)
撮像素子に一体に設けて用いる集光素子であって、輪帯
の中心を軸とした同一軸上に正の屈折力を有する屈折率
分布領域と負の屈折力を有する屈折率分布領域とを備え
たことを特徴とする固体撮像素子用一体型集光素子。1. A condensing element used integrally with a solid-state imaging device in which a photoelectric conversion part of a pixel has a substantially annular shape, and has a positive refractive power on the same axis with the center of the annular zone as an axis. An integrated light-collecting device for a solid-state imaging device, comprising a refractive index distribution region and a refractive index distribution region having a negative refractive power.
を有する屈折率分布領域の有効径が前記光電変換部の最
外径よりも大きく、かつ、少なくとも光軸近傍において
前記負の屈折力を有する屈折率分布領域の該屈折力の絶
対値が、前記正の屈折力を有する屈折率分布領域の該屈
折力の絶対値より大きいことを特徴とする請求項１記載
の固体撮像素子用一体型集光素子。2. In the condensing element, the effective diameter of the refractive index distribution region having the positive refractive power is larger than the outermost diameter of the photoelectric conversion section, and the negative refractive power is at least near the optical axis. 2. The solid-state image pickup device according to claim 1, wherein the absolute value of the refractive power of the refractive index distribution region having the refractive index is larger than the absolute value of the refractive power of the refractive index distribution region having the positive refractive power. Body type light condensing element.
一体型集光素子を製造するにあたり、光電変換部の中心
軸上の集光素子用基板の所定位置に屈折率分布領域を形
成した後、同軸上に前記屈折率分布とは反対の屈折力を
有する屈折率分布領域を積層することを特徴とする固体
撮像素子用一体型集光素子の製造方法。3. In manufacturing the integrated light-collecting device for a solid-state image pickup device according to claim 1, a refractive index distribution region is formed at a predetermined position of a light-collecting device substrate on a central axis of a photoelectric conversion unit. After that, a method for manufacturing an integrated light-collecting device for a solid-state image pickup device, which comprises coaxially stacking a refractive index distribution region having a refractive power opposite to the refractive index distribution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6142412A JPH07325263A (en) | 1994-06-01 | 1994-06-01 | Integral type condenser element for solid-state image pickup element and its production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6142412A JPH07325263A (en) | 1994-06-01 | 1994-06-01 | Integral type condenser element for solid-state image pickup element and its production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07325263A true JPH07325263A (en) | 1995-12-12 |
Family
ID=15314741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6142412A Withdrawn JPH07325263A (en) | 1994-06-01 | 1994-06-01 | Integral type condenser element for solid-state image pickup element and its production |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07325263A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010243682A (en) * | 2009-04-03 | 2010-10-28 | Canon Inc | Refractive index distributed optical element and imaging device including the refractive index distributed optical element |
| JP2013506884A (en) * | 2009-10-06 | 2013-02-28 | デューク ユニバーシティ | Gradient-index lens and method without spherical aberration |
| KR101435519B1 (en) * | 2008-07-24 | 2014-08-29 | 삼성전자주식회사 | Image sensor having light focusing structure |
-
1994
- 1994-06-01 JP JP6142412A patent/JPH07325263A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101435519B1 (en) * | 2008-07-24 | 2014-08-29 | 삼성전자주식회사 | Image sensor having light focusing structure |
| JP2010243682A (en) * | 2009-04-03 | 2010-10-28 | Canon Inc | Refractive index distributed optical element and imaging device including the refractive index distributed optical element |
| JP2013506884A (en) * | 2009-10-06 | 2013-02-28 | デューク ユニバーシティ | Gradient-index lens and method without spherical aberration |
| US8848295B2 (en) | 2009-10-06 | 2014-09-30 | Duke University | Gradient index lenses and methods with zero spherical aberration |
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| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
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