JP2002324899A - Method for manufacturing solid-state image pickup element - Google Patents
Method for manufacturing solid-state image pickup elementInfo
- Publication number
- JP2002324899A JP2002324899A JP2001127053A JP2001127053A JP2002324899A JP 2002324899 A JP2002324899 A JP 2002324899A JP 2001127053 A JP2001127053 A JP 2001127053A JP 2001127053 A JP2001127053 A JP 2001127053A JP 2002324899 A JP2002324899 A JP 2002324899A
- Authority
- JP
- Japan
- Prior art keywords
- film
- hydrogen
- nitride film
- silicon nitride
- light receiving
- 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
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 15
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 36
- 239000001257 hydrogen Substances 0.000 claims abstract description 36
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 34
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 34
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims abstract description 34
- 238000000137 annealing Methods 0.000 claims abstract description 25
- 239000000758 substrate Substances 0.000 claims abstract description 23
- 238000005268 plasma chemical vapour deposition Methods 0.000 claims abstract description 5
- 238000012546 transfer Methods 0.000 claims description 42
- 238000003384 imaging method Methods 0.000 claims description 19
- 238000010438 heat treatment Methods 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 9
- 229910052594 sapphire Inorganic materials 0.000 claims 1
- 239000010980 sapphire Substances 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 17
- 230000015572 biosynthetic process Effects 0.000 abstract description 9
- 150000004767 nitrides Chemical class 0.000 description 12
- 230000035945 sensitivity Effects 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 6
- 229910052710 silicon Inorganic materials 0.000 description 6
- 239000010703 silicon Substances 0.000 description 6
- 238000002161 passivation Methods 0.000 description 5
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 229910052814 silicon oxide Inorganic materials 0.000 description 4
- 241000519995 Stachys sylvatica Species 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 230000003595 spectral effect Effects 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000005380 borophosphosilicate glass Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000002230 thermal chemical vapour deposition Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Landscapes
- Transforming Light Signals Into Electric Signals (AREA)
- Solid State Image Pick-Up Elements (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、例えば紫外光領域
の感度の向上を図った固体撮像素子の製造方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solid-state image pickup device with an improved sensitivity in, for example, an ultraviolet region.
【０００２】[0002]
【従来の技術】従来、ＣＣＤ（電荷結合素子）を用いた
固体撮像素子は、例えば、Ｎ型シリコン基板表面に形成
されたＰ型ウェル領域からなるオーバーフローバリア層
の上に、フォトセンサからなる受光部を構成するＮ型の
信号電荷蓄積領域と、垂直シフトレジスタを構成するＮ
型の転送チャネル領域とが形成され、この転送チャネル
領域の上にゲート酸化膜を介して多結晶シリコンからな
る転送電極が選択的に形成された構造を有している。そ
して、この転送電極の上に転送チャネル領域への光の入
射を遮るための金属遮光膜を選択的に形成した後、パシ
ベーション膜として、シリコン窒化膜をプラズマＣＶＤ
法によって基板全面に成膜する構成が知られている（特
開昭６０−６６８２６号公報）。2. Description of the Related Art Conventionally, a solid-state imaging device using a CCD (Charge Coupled Device) has, for example, a light receiving device comprising a photo sensor on an overflow barrier layer comprising a P-type well region formed on the surface of an N-type silicon substrate. And an N-type signal charge storage region forming a vertical shift register.
A transfer channel region is formed, and a transfer electrode made of polycrystalline silicon is selectively formed on the transfer channel region via a gate oxide film. Then, after selectively forming a metal light-shielding film on the transfer electrode for blocking light from entering the transfer channel region, a silicon nitride film is formed as a passivation film by plasma CVD.
A configuration in which a film is formed on the entire surface of a substrate by a method is known (Japanese Patent Application Laid-Open No. Sho 60-66826).
【０００３】上記シリコン窒化膜は、パシベーション膜
として要求される耐湿性等を備えるだけでなく、所定の
熱処理を施すことによってシリコン基板側へ水素を供給
する水素含有膜あるいは水素供給膜としても機能する。
シリコン基板は、上記窒化膜から水素を供給されること
によって基板界面電位の低減が図られ、暗電流や白キズ
の発生が抑制される。このような作用は、一般に水素ア
ニール効果として知られている。The silicon nitride film has not only the moisture resistance required as a passivation film, but also functions as a hydrogen-containing film or a hydrogen supply film that supplies hydrogen to the silicon substrate by performing a predetermined heat treatment. .
By supplying hydrogen from the nitride film to the silicon substrate, the substrate interface potential is reduced, and the generation of dark current and white flaws is suppressed. Such an effect is generally known as a hydrogen annealing effect.
【０００４】ところが、受光部の形成領域上にシリコン
窒化膜が存在していると、これら受光部とシリコン窒化
膜の間に介在するゲート酸化膜（酸化シリコン）との屈
折率の相違から、分光感度の低下をもたらしたり、スミ
ア現象を発生させるという問題がある。また、紫外光を
利用した顕微鏡や欠陥検出器など、紫外領域の感度の向
上を目的としたＣＣＤ固体撮像素子にあっては、シリコ
ン窒化膜による紫外光の吸収が問題となる。However, if a silicon nitride film is present on the region where the light receiving portion is to be formed, the spectral difference is caused by the difference in the refractive index between the light receiving portion and the gate oxide film (silicon oxide) interposed between the silicon nitride film and the silicon nitride film. There are problems that the sensitivity is lowered and that a smear phenomenon occurs. Further, in a CCD solid-state imaging device for improving sensitivity in an ultraviolet region, such as a microscope or a defect detector using ultraviolet light, absorption of ultraviolet light by a silicon nitride film becomes a problem.
【０００５】そのため、受光部の形成領域上にはシリコ
ン窒化膜は形成されないのが望ましいとされるが、反
面、水素アニール効果が望めなくなるのが問題となる。For this reason, it is desirable that no silicon nitride film be formed on the region where the light receiving section is formed, but on the other hand, there is a problem that the hydrogen annealing effect cannot be expected.
【０００６】そこで、特開平８−３２０４５号公報に
は、遮光膜が形成された基板全面にシリコン窒化膜を形
成した後（窒化膜形成工程）、異方性エッチングによっ
て受光部の形成領域上にあるシリコン窒化膜を選択的に
除去し（窒化膜除去工程）、次いで、所定の熱処理を基
板全面に施すことにより（アニール工程）、水素アニー
ル効果を持たせて上記問題の解決を図った固体撮像素子
の製造方法が開示されている（図６）。Japanese Patent Application Laid-Open No. 8-32045 discloses that after forming a silicon nitride film on the entire surface of a substrate on which a light-shielding film is formed (nitride film forming step), the silicon nitride film is formed on the light receiving portion forming region by anisotropic etching. A solid-state imaging device in which a certain silicon nitride film is selectively removed (nitride film removal process) and then a predetermined heat treatment is performed on the entire surface of the substrate (annealing process) to provide a hydrogen annealing effect to solve the above problem. A method for manufacturing an element is disclosed (FIG. 6).
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、上記公
報に記載の方法では、遮光膜に用いる金属膜層による水
素基の吸収もあるため、受光部にシリコン窒化膜がない
状態で熱処理を施しても十分な水素アニール効果が望め
ず、したがって暗電流や白キズの抑制効果としては大き
な効果を期待することができないのが実情である。However, in the method described in the above publication, since the metal film layer used for the light-shielding film also absorbs hydrogen groups, the heat treatment can be performed without the silicon nitride film in the light receiving portion. In fact, a sufficient hydrogen annealing effect cannot be expected, so that a large effect cannot be expected as an effect of suppressing dark current and white flaws.
【０００８】本発明は上述の問題に鑑みてなされ、十分
な水素アニール効果を与えて暗電流や白キズの発生を抑
制しながら、受光部の形成領域にシリコン窒化膜が形成
されない固体撮像素子の製造方法を提供することを課題
とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides a solid-state imaging device in which a silicon nitride film is not formed in a region where a light receiving portion is formed while giving a sufficient hydrogen annealing effect to suppress generation of dark current and white flaws. It is an object to provide a manufacturing method.
【０００９】[0009]
【課題を解決するための手段】以上の課題を解決するに
当たり、本発明に係る固体撮像素子の製造方法は、受光
部を含む基板全域に水素含有膜を形成する水素含有膜形
成工程と、基板の全面に熱処理を施す熱処理工程と、熱
処理した受光部の形成領域にある水素含有膜を選択的に
除去する除去工程とを有することを特徴とする。In order to solve the above-mentioned problems, a method for manufacturing a solid-state imaging device according to the present invention includes a hydrogen-containing film forming step of forming a hydrogen-containing film over the entire substrate including a light receiving portion; And a removing step of selectively removing the hydrogen-containing film in the region where the light-receiving portion is formed after the heat treatment.
【００１０】本発明は、基板に形成した水素含有膜を受
光部の形成領域から除去する前に、基板全面に所定の熱
処理を行うようにしているので、基板に対して十分な水
素アニール効果を持たせることができ、暗電流や白キズ
の発生を効果的に抑制することが可能となる。According to the present invention, a predetermined heat treatment is performed on the entire surface of the substrate before the hydrogen-containing film formed on the substrate is removed from the region where the light receiving section is formed. And the occurrence of dark current and white spots can be effectively suppressed.
【００１１】[0011]
【発明の実施の形態】以下、本発明の実施の形態につい
て図面を参照して説明する。本実施の形態では、インタ
ーライン転送（ＩＴ）方式のＣＣＤイメージセンサに適
用される固体撮像素子の製造方法について説明する。Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, a method for manufacturing a solid-state imaging device applied to an interline transfer (IT) type CCD image sensor will be described.
【００１２】図１に示すように、ＣＣＤイメージセンサ
１は、水平方向及び垂直方向に二次元的に配置されたフ
ォトセンサからなる複数の受光部２と、これらの受光部
２のうち、列方向に配列された受光部２に対して共通と
される複数本の垂直転送レジスタ３と、これらの垂直転
送レジスタ３の端部に共通に配置される水平転送レジス
タ４と、この水平転送レジスタ４の端部に配置される出
力部５等から構成される。As shown in FIG. 1, a CCD image sensor 1 has a plurality of light receiving sections 2 each composed of a photo sensor arranged two-dimensionally in a horizontal direction and a vertical direction. , A plurality of vertical transfer registers 3 which are common to the light receiving units 2 arranged in a horizontal direction, a horizontal transfer register 4 commonly arranged at an end of the vertical transfer registers 3, It comprises an output unit 5 and the like arranged at the end.
【００１３】各受光部２において光電変換された信号電
荷は、読出しゲート部６を介して垂直転送レジスタ３へ
転送される。垂直転送レジスタ３は例えば４枚の転送電
極を１組として多数組、垂直方向へ順次配列されて形成
されたもので、垂直転送期間（水平ブランキング期間）
内にこれら４枚の転送電極に対して位相の異なる垂直転
送パルスが印加されることによって各転送電極下のポテ
ンシャル分布が順次変化し、これにより信号電荷が順次
水平転送レジスタ４へ転送される。The signal charge photoelectrically converted in each light receiving section 2 is transferred to the vertical transfer register 3 via the read gate section 6. The vertical transfer register 3 is formed by, for example, a large number of sets each including four transfer electrodes, which are sequentially arranged in the vertical direction. A vertical transfer period (a horizontal blanking period)
By applying vertical transfer pulses having different phases to these four transfer electrodes, the potential distribution under each transfer electrode sequentially changes, whereby signal charges are sequentially transferred to the horizontal transfer register 4.
【００１４】一方の水平転送レジスタ４は、例えば２枚
の転送電極を１組として多数組、水平方向へ順次配列さ
れて形成されたもので、水平転送期間（垂直ブランキン
グ期間）内にこれら２枚の転送電極に対して位相の異な
る水平転送パルスが印加されることによって各転送電極
下のポテンシャル分布が順次変化し、これにより信号電
荷が順次出力部５へ転送される。転送された信号電荷
は、出力部５において電圧信号に変換され、図示しない
信号処理系にて処理される。One horizontal transfer register 4 is formed by, for example, two sets of transfer electrodes as one set and being sequentially arranged in the horizontal direction. These two sets are arranged within a horizontal transfer period (vertical blanking period). By applying horizontal transfer pulses having different phases to one transfer electrode, the potential distribution under each transfer electrode is sequentially changed, whereby signal charges are sequentially transferred to the output unit 5. The transferred signal charges are converted into voltage signals at the output unit 5 and processed by a signal processing system (not shown).
【００１５】図２は、図１における［２］−［２］線方
向における固体撮像素子の断面構造を模式的に示してい
る。Ｎ型シリコン基板１１に形成したＰ型ウェル領域１
２の表面に、受光部２を形成するためのＮ型の信号電荷
蓄積領域１３と、垂直転送レジスタ３を形成するための
Ｎ型の電荷転送領域１４と、Ｐ+ 型のチャネルストッパ
領域１５とが形成されている。信号電荷蓄積領域１３と
電荷転送領域１４との間のＰ型領域は、読出しゲート部
１６を構成している。FIG. 2 schematically shows a cross-sectional structure of the solid-state imaging device taken along the line [2]-[2] in FIG. P-type well region 1 formed on N-type silicon substrate 11
2, an N-type signal charge accumulation region 13 for forming the light receiving section 2, an N-type charge transfer region 14 for forming the vertical transfer register 3, and a P + -type channel stopper region 15. Is formed. The P-type region between the signal charge storage region 13 and the charge transfer region 14 forms the read gate unit 16.
【００１６】電荷転送領域１４の上にはゲート絶縁膜１
７を介して多結晶シリコン層からなる転送電極１８が選
択形成されており、これら電荷転送領域１４、ゲート絶
縁膜１７及び転送電極１８によって垂直転送レジスタ３
が構成される。なお、転送電極１８は１層目の多結晶シ
リコン層及び２層目の多結晶シリコン層から構成される
が、図では１層目の多結晶シリコン層のみを示してい
る。On the charge transfer region 14, the gate insulating film 1 is formed.
7, a transfer electrode 18 made of a polycrystalline silicon layer is selectively formed. The charge transfer region 14, the gate insulating film 17, and the transfer electrode 18 allow the vertical transfer register 3 to be formed.
Is configured. Although the transfer electrode 18 includes a first polycrystalline silicon layer and a second polycrystalline silicon layer, only the first polycrystalline silicon layer is shown in FIG.
【００１７】転送電極１８の表面には熱酸化によるシリ
コン酸化膜１９が形成され、その上に遮光膜２０が形成
されている。遮光膜２０は受光部２の形成領域において
選択的にエッチング除去されており、光は、このエッチ
ング除去によって形成された開口２０ａを通じて受光部
２に入射される。遮光膜２０の形成領域上には、パシベ
ーション膜としてシリコン窒化膜２１が形成されてお
り、遮光膜２０と同様、受光部２の形成領域において選
択的にエッチング除去されている。A silicon oxide film 19 is formed on the surface of the transfer electrode 18 by thermal oxidation, and a light-shielding film 20 is formed thereon. The light-shielding film 20 is selectively etched away in a region where the light receiving section 2 is formed, and light is incident on the light receiving section 2 through an opening 20a formed by this etching. A silicon nitride film 21 is formed as a passivation film on the region where the light-shielding film 20 is formed. Like the light-shielding film 20, the silicon nitride film 21 is selectively etched away in the region where the light-receiving unit 2 is formed.
【００１８】シリコン窒化膜２１及び受光部２の全面に
は平坦化膜２２が形成される。平坦化膜２２には必要に
応じてインナーレンズ２３やカラーフィルタ（図示略）
が設けられると共に、平坦化膜２２の上にはトップレン
ズ（図示略）等が形成される。A flattening film 22 is formed on the entire surface of the silicon nitride film 21 and the light receiving section 2. The flattening film 22 has an inner lens 23 and a color filter (not shown) as necessary.
Is provided, and a top lens (not shown) and the like are formed on the flattening film 22.
【００１９】以上のように構成される本実施の形態の固
体撮像素子は、受光部２の形成領域にシリコン窒化膜２
１は形成されておらず、したがって分光感度の低下やス
ミアの発生を防止することができる。また、紫外光領域
の感度の向上を目的とした固体撮像素子にあっては、波
長４００ｎｍ以下の紫外光領域を感度良く受光すること
ができる。The solid-state imaging device according to the present embodiment configured as described above has a silicon nitride film 2
No. 1 is not formed, so that a decrease in spectral sensitivity and generation of smear can be prevented. Also, in a solid-state imaging device for the purpose of improving the sensitivity in the ultraviolet light region, the ultraviolet light region having a wavelength of 400 nm or less can be received with high sensitivity.
【００２０】次に、以上のように構成される固体撮像素
子の製造方法について図３から図５を参照して説明す
る。図５は、本実施の形態による固体撮像素子の製造フ
ローを示しており、遮光膜形成工程Ｓ１と、窒化膜形成
工程Ｓ２と、アニール工程Ｓ３と、窒化膜除去工程Ｓ４
と、平坦化膜形成工程Ｓ５とからなる。ここでは、受光
部２及び転送電極１８の上にシリコン酸化膜１９を形成
した状態（図３Ａ）から後のプロセスについて説明す
る。Next, a method of manufacturing the solid-state imaging device having the above structure will be described with reference to FIGS. FIG. 5 shows a manufacturing flow of the solid-state imaging device according to the present embodiment, which includes a light-shielding film forming step S1, a nitride film forming step S2, an annealing step S3, and a nitride film removing step S4.
And a flattening film forming step S5. Here, the process after the state where the silicon oxide film 19 is formed on the light receiving section 2 and the transfer electrode 18 (FIG. 3A) will be described.
【００２１】（遮光膜形成工程Ｓ１）遮光膜形成工程Ｓ
１では、図３Ｂに示すようにシリコン酸化膜１９上にＣ
ＶＤ法によりタングステン膜２０が成膜される。遮光膜
２０の膜厚は、例えば３００〜３２５ｎｍとされる。そ
の後、公知のフォトリソグラフィ法を用いて受光部２の
形成領域にある遮光膜２０がドライエッチング法によっ
て選択的に除去される。(Light shielding film forming step S1) Light shielding film forming step S
In FIG. 1, C is formed on the silicon oxide film 19 as shown in FIG.
The tungsten film 20 is formed by the VD method. The thickness of the light shielding film 20 is, for example, 300 to 325 nm. Thereafter, the light-shielding film 20 in the formation region of the light receiving section 2 is selectively removed by a dry etching method using a known photolithography method.
【００２２】（窒化膜形成工程Ｓ２）窒化膜形成工程Ｓ
２では、図４Ａに示すように遮光膜２０及び受光部２を
含む全面にプラズマＣＶＤ法によりシリコン窒化膜２１
が成膜される。窒化膜２１の膜厚は、例えば３２５ｎｍ
とされる。窒化膜２１は、パシベーション膜としてのほ
かに、水素を十分に含んだ水素含有膜として形成され
る。(Nitride film formation step S2) Nitride film formation step S
4A, a silicon nitride film 21 is formed on the entire surface including the light shielding film 20 and the light receiving portion 2 by the plasma CVD method, as shown in FIG.
Is formed. The thickness of the nitride film 21 is, for example, 325 nm.
It is said. The nitride film 21 is formed not only as a passivation film but also as a hydrogen-containing film sufficiently containing hydrogen.
【００２３】（アニール工程Ｓ３）アニール工程Ｓ３
は、受光部２を含む基板全面に窒化膜２１を形成した直
後に行われる。本実施の形態では略３８０℃の温度で１
時間、いわゆる低温アニールと呼ばれる熱処理が行われ
る。この処理により、シリコン窒化膜２１中に含まれる
水素が、基板１１側に拡散する。この水素拡散によって
基板界面が水素化され、例えばシリコン結晶中の微小欠
陥に生じているダングリングボンドが水素によって終端
されて、イメージセンサのノイズとなる暗電流、白キズ
の発生が抑制される。(Annealing Step S3) Annealing Step S3
Is performed immediately after the nitride film 21 is formed on the entire surface of the substrate including the light receiving section 2. In this embodiment, a temperature of about 380 ° C.
Time, heat treatment called so-called low temperature annealing is performed. By this processing, hydrogen contained in the silicon nitride film 21 diffuses to the substrate 11 side. Due to this hydrogen diffusion, the interface of the substrate is hydrogenated, and, for example, dangling bonds generated in minute defects in the silicon crystal are terminated by hydrogen, thereby suppressing the generation of dark current and white flaws, which are noises of the image sensor.
【００２４】特に本実施の形態では、受光部２の形成領
域にシリコン窒化膜２１が残留している状態で上記のア
ニール処理がなされるので、基板１１に対して十分な量
の水素を供給することができ、暗電流、白キズの発生抑
制効果を高めることができる。In particular, in the present embodiment, since the above-described annealing is performed in a state where the silicon nitride film 21 remains in the formation region of the light receiving section 2, a sufficient amount of hydrogen is supplied to the substrate 11. As a result, the effect of suppressing the occurrence of dark current and white flaws can be enhanced.
【００２５】（窒化膜除去工程Ｓ４）窒化膜除去工程Ｓ
４では、上記のアニール処理がなされた後に行われ、図
４Ｂに示すように受光部２の形成領域にあるシリコン窒
化膜２１が、公知のフォトリソグラフィ法を用いたドラ
イエッチング法により選択的に除去される。(Nitride film removing step S4) Nitride film removing step S
4, the annealing is performed after the above-described annealing process is performed. As shown in FIG. 4B, the silicon nitride film 21 in the formation region of the light receiving unit 2 is selectively removed by a dry etching method using a known photolithography method. Is done.
【００２６】（平坦化膜形成工程Ｓ５）平坦化膜形成工
程Ｓ５では、基板全面に平坦化膜２２としてプラズマＴ
ＥＯＳ酸化膜あるいはＢＰＳＧが成膜される。平坦化膜
２２の膜厚は、例えば５０００ｎｍとされる。以降、固
体撮像素子のタイプに応じてインナレンズ、カラーフィ
ルタ、トップレンズ等が形成される。(Planarizing Film Forming Step S5) In the planarizing film forming step S5, a plasma T
An EOS oxide film or BPSG is formed. The thickness of the planarizing film 22 is, for example, 5000 nm. Thereafter, an inner lens, a color filter, a top lens, and the like are formed according to the type of the solid-state imaging device.
【００２７】以上のように、本実施の形態によれば、受
光部２の形成領域にあるシリコン窒化膜２１をエッチン
グ除去する前にアニール処理を行うようにしているの
で、基板に対して十分な水素アニール効果を付与するこ
とができ、暗電流、白キズ発生の抑制効果を高めること
ができる。また、アニール処理後は、受光部２の形成領
域にあるシリコン窒化膜２１を除去しているので、分光
感度の低下やスミアの発生を抑えることができ、あるい
は、紫外線領域の感度向上を図ることができる。As described above, according to the present embodiment, the annealing treatment is performed before the silicon nitride film 21 in the region where the light receiving section 2 is formed is removed by etching. A hydrogen annealing effect can be imparted, and the effect of suppressing dark current and white spots can be enhanced. Further, since the silicon nitride film 21 in the region where the light receiving section 2 is formed is removed after the annealing process, it is possible to suppress a decrease in spectral sensitivity and generation of smear, or to improve a sensitivity in an ultraviolet region. Can be.
【００２８】また、シリコン窒化膜２１の成膜をプラズ
マＣＶＤ法で行うようにしているので、基板を高温にさ
らすことなくシリコン窒化膜２１を成膜することがで
き、したがって高温による受光部２のポテンシャルの変
動を防止できる。同様に、アニール工程では略３８０℃
の低温アニールとしているので、高温による特性の変動
を回避しながら、十分な水素アニール効果を得ることが
できる。Further, since the silicon nitride film 21 is formed by the plasma CVD method, the silicon nitride film 21 can be formed without exposing the substrate to a high temperature. Potential fluctuation can be prevented. Similarly, in the annealing step, approximately 380 ° C.
, A sufficient hydrogen annealing effect can be obtained while avoiding fluctuations in characteristics due to high temperatures.
【００２９】以上、本発明の実施の形態について説明し
たが、勿論、本発明はこれに限定されることなく、本発
明の技術的思想に基づいて種々の変形が可能である。Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention.
【００３０】例えば以上の実施の形態では、プラズマＣ
ＶＤ法により成膜したシリコン窒化膜２１を水素含有膜
として説明したが、これに限らない。例えば、水素還元
雰囲気中で成膜したアルミニウムからなる遮光膜を水素
含有膜とすることができる。この場合、遮光膜形成後に
所定の熱処理を施すことによって水素アニール効果を得
ることができる。また、通常のＣＶＤ法（熱ＣＶＤ法）
で成膜したシリコン窒化膜にも同様な機能をもたせるこ
とができる。For example, in the above embodiment, the plasma C
Although the silicon nitride film 21 formed by the VD method has been described as a hydrogen-containing film, it is not limited to this. For example, a light-shielding film made of aluminum formed in a hydrogen reducing atmosphere can be a hydrogen-containing film. In this case, by performing a predetermined heat treatment after the formation of the light shielding film, a hydrogen annealing effect can be obtained. Ordinary CVD method (thermal CVD method)
A similar function can be provided to the silicon nitride film formed by the method described above.
【００３１】[0031]
【発明の効果】以上述べたように、本発明の固体撮像素
子の製造方法によれば、受光部の形成領域にある水素含
有膜を除去する前に所定の処理を行うようにしているの
で、基板に対して十分な水素アニール効果を付与するこ
とができ、暗電流、白キズ発生の抑制効果を高めること
ができる。As described above, according to the method of manufacturing a solid-state imaging device of the present invention, a predetermined process is performed before removing a hydrogen-containing film in a region where a light receiving section is formed. A sufficient hydrogen annealing effect can be imparted to the substrate, and the effect of suppressing dark current and white spots can be enhanced.
【００３２】請求項２の発明によれば、基板を高温にさ
らすことなく水素含有膜であるシリコン窒化膜を成膜す
ることができ、したがって高温による受光部のポテンシ
ャルの変動を防止できる。According to the second aspect of the present invention, the silicon nitride film, which is a hydrogen-containing film, can be formed without exposing the substrate to a high temperature. Therefore, a change in the potential of the light receiving portion due to the high temperature can be prevented.
【００３３】そして請求項３の発明によれば、高温によ
る素子特性の変動を回避しながら、十分な水素アニール
効果を得ることができる。According to the third aspect of the present invention, a sufficient hydrogen annealing effect can be obtained while avoiding variations in device characteristics due to high temperatures.
【図１】本発明の実施の形態に適用される固体撮像素子
の構成を示す説明図である。FIG. 1 is an explanatory diagram illustrating a configuration of a solid-state imaging device applied to an embodiment of the present invention.
【図２】図１における［２］−［２］線方向の素子の断
面構造を示す図である。FIG. 2 is a diagram showing a cross-sectional structure of the element taken along a line [2]-[2] in FIG.
【図３】本発明の実施の形態による固体撮像素子の製造
プロセスを示す断面図であり、Ａは転送電極上に熱酸化
膜形成工程を示し、Ｂは遮光膜形成工程を示している。3A and 3B are cross-sectional views illustrating a manufacturing process of the solid-state imaging device according to the embodiment of the present invention, wherein A illustrates a thermal oxide film forming step on a transfer electrode, and B illustrates a light shielding film forming step.
【図４】本発明の実施の形態による固体撮像素子の製造
プロセスを示す断面図であり、Ａはシリコン窒化膜形成
工程及びアニール工程を示し、Ｂはシリコン窒化膜除去
工程を示し、Ｃは平坦化膜形成工程を示している。FIG. 4 is a cross-sectional view showing a manufacturing process of the solid-state imaging device according to the embodiment of the present invention, wherein A shows a silicon nitride film forming step and an annealing step, B shows a silicon nitride film removing step, and C shows a flat surface. 3 shows a passivation film forming step.
【図５】本発明の実施の形態による固体撮像素子の製造
方法を説明する工程フロー図である。FIG. 5 is a process flowchart illustrating a method for manufacturing a solid-state imaging device according to an embodiment of the present invention.
【図６】従来の固体撮像素子の製造方法を説明する工程
フロー図である。FIG. 6 is a process flowchart illustrating a conventional method for manufacturing a solid-state imaging device.
１…イメージセンサ（固体撮像素子）、２…受光部、３
…垂直転送レジスタ、４…水平転送レジスタ、５…出力
部、６…読出しゲート部、１１…シリコン基板、１３…
信号電荷蓄積領域、１４…電荷転送領域、１７…ゲート
絶縁膜、１８…転送電極、２０…遮光膜、２１…シリコ
ン窒化膜（水素含有膜）、２２…平坦化膜。DESCRIPTION OF SYMBOLS 1 ... Image sensor (solid-state image sensor), 2 ... Light receiving part, 3
... vertical transfer register, 4 ... horizontal transfer register, 5 ... output section, 6 ... readout gate section, 11 ... silicon substrate, 13 ...
Signal charge storage region, 14: charge transfer region, 17: gate insulating film, 18: transfer electrode, 20: light shielding film, 21: silicon nitride film (hydrogen-containing film), 22: flattening film.
Claims (3)
列形成され、前記電荷転送領域上にゲート絶縁膜を介し
て転送電極が選択的に形成される固体撮像素子の製造方
法であって、 前記受光部を含む基板全域に水素含有膜を形成する水素
含有膜形成工程と、 前記基板の全面に所定の熱処理を施す熱処理工程と、 前記熱処理した受光部の形成領域にある前記水素含有膜
を選択的に除去する除去工程とを有することを特徴とす
る固体撮像素子の製造方法。1. A method of manufacturing a solid-state imaging device, wherein a light receiving portion and a charge transfer region are arranged and formed on a substrate surface, and a transfer electrode is selectively formed on the charge transfer region via a gate insulating film. A hydrogen-containing film forming step of forming a hydrogen-containing film over the entire substrate including the light-receiving unit; a heat-treating step of performing a predetermined heat treatment on the entire surface of the substrate; and the hydrogen-containing film in a region where the heat-treated light-receiving unit is formed. And a removing step of selectively removing sapphire.
よって成膜されるシリコン窒化膜であることを特徴とす
る請求項１に記載の固体撮像素子の製造方法。2. The method according to claim 1, wherein the hydrogen-containing film is a silicon nitride film formed by a plasma CVD method.
ール処理であることを特徴とする請求項１に記載の固体
撮像素子の製造方法。3. The method according to claim 1, wherein the predetermined heat treatment is an annealing process at about 380 ° C.
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| JP2001127053A JP2002324899A (en) | 2001-04-25 | 2001-04-25 | Method for manufacturing solid-state image pickup element |
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| US7935988B2 (en) | 2005-09-05 | 2011-05-03 | Sony Corporation | Method of manufacturing solid state imaging device, solid state imaging device, and camera using solid state imaging device |
| US9530819B2 (en) | 2014-08-06 | 2016-12-27 | Renesas Electronics Corporation | Manufacturing method of semiconductor integrated circuit device |
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