JPH07120776B2 - Schottky type image sensor manufacturing method - Google Patents
Schottky type image sensor manufacturing methodInfo
- Publication number
- JPH07120776B2 JPH07120776B2 JP63108636A JP10863688A JPH07120776B2 JP H07120776 B2 JPH07120776 B2 JP H07120776B2 JP 63108636 A JP63108636 A JP 63108636A JP 10863688 A JP10863688 A JP 10863688A JP H07120776 B2 JPH07120776 B2 JP H07120776B2
- Authority
- JP
- Japan
- Prior art keywords
- light receiving
- nitride film
- film
- oxide film
- image sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 150000004767 nitrides Chemical class 0.000 claims description 18
- 239000012535 impurity Substances 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 8
- 230000003647 oxidation Effects 0.000 claims description 4
- 238000007254 oxidation reaction Methods 0.000 claims description 4
- 239000004065 semiconductor Substances 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 7
- 229910052814 silicon oxide Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 238000000059 patterning Methods 0.000 description 5
- 229920002120 photoresistant polymer Polymers 0.000 description 5
- 238000005530 etching Methods 0.000 description 4
- 229910052698 phosphorus Inorganic materials 0.000 description 4
- 239000011574 phosphorus Substances 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 4
- 229920005591 polysilicon Polymers 0.000 description 4
- -1 boron ions Chemical class 0.000 description 3
- ZXEYZECDXFPJRJ-UHFFFAOYSA-N $l^{3}-silane;platinum Chemical compound [SiH3].[Pt] ZXEYZECDXFPJRJ-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 229910021339 platinum silicide Inorganic materials 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Element Separation (AREA)
- Light Receiving Elements (AREA)
- Electrodes Of Semiconductors (AREA)
- Solid State Image Pick-Up Elements (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はショットキ型イメージセンサの製造方法に関す
るものである。The present invention relates to a method of manufacturing a Schottky type image sensor.
従来、ショットキ型イメージセンサはショットキダイオ
ードとMOSスイッチとを組み合わせたもの、あるいは電
荷結合素子とを組み合わせたもの等が提案され、また、
これが製造されてきた。（M.Denda,M.Kimata,N.Yutani,
N.Tsubouchi,and S.Vemotsy“A Pt Si Schottky−Barri
erinfrared MOS area image with large fillfactor"in
IEDM tech.Dig.,pp.722−725,1983,W.F.Kosonocky and
H.Elabd,“High Performance Schottky−Barrier IR−
CCD Image Sensors"Jpn.J.Appl.Phys.,vol.22（1983）S
uppl.22−1,pp.103−108など） 電荷結合素子ECとショットキダイオードSDとを組み合わ
せたイメージセンサの一例の主な製造工程を第２図に示
す。第２図（ａ）において、Ｐ型Si基板１上に第１シリ
コン酸化膜２、シリコン窒化膜を成長させた後、フォト
レジスト法により窒化膜のパターン３を形成し、ショッ
トキダイオードSDの形成部分中央にレジスト材のパター
ン15を形成する。しかる後、第２図（ｂ）のようにＮ型
不純物、例えばリンをイオン注入し、熱酸化を行ない、
N-型CCD活性領域７とN-型ガードリング６および第二酸
化膜層５を形成する。第２図（Ｃ）において、Ｐ型の不
純物、例えばボロンのイオン注入を行ない、チャネルス
トッパ８を形成する。次いで所定の厚さのシリコン酸化
膜を成長し、その上にポリシリコンを堆積する。該シリ
コン酸化膜およびポリシリコンをパターニングすること
により、電荷結合素子ECのゲート酸化膜10およびゲート
電極11を形成し、さらにレジスト材のパターン12を形成
する。次いでＮ型不純物、例えばリンのイオン注入を行
ない、N+領域９を形成する。第２図（ｄ）において、絶
縁膜、例えばPSG膜を堆積、フォトレジスト法により絶
縁膜のパターン13を形成する。金属膜、例えば白金膜を
堆積し、熱処理を施した後、所定のエッチング液により
ショットキダイオード金属電極層14、例えば白金シリサ
イド以外をエッチング除去して完成する。Conventionally, as the Schottky type image sensor, a combination of a Schottky diode and a MOS switch, a combination of a charge coupled device, or the like has been proposed.
It has been manufactured. (M.Denda, M.Kimata, N.Yutani,
N.Tsubouchi, and S.Vemotsy “A Pt Si Schottky-Barri
erinfrared MOS area image with large fillfactor "in
IEDM tech.Dig., Pp.722-725,1983, WFKosonocky and
H. Elabd, “High Performance Schottky-Barrier IR-
CCD Image Sensors "Jpn.J.Appl.Phys., Vol.22 (1983) S
The main manufacturing process of an example of an image sensor in which the charge coupled device EC and the Schottky diode SD are combined is shown in FIG. In FIG. 2 (a), after a first silicon oxide film 2 and a silicon nitride film are grown on a P-type Si substrate 1, a nitride film pattern 3 is formed by a photoresist method to form a Schottky diode SD formation portion. A pattern 15 of resist material is formed in the center. Then, as shown in FIG. 2B, N-type impurities such as phosphorus are ion-implanted and thermal oxidation is performed.
An N − type CCD active region 7, an N − type guard ring 6 and a second dioxide layer 5 are formed. In FIG. 2C, P-type impurities such as boron ions are implanted to form the channel stopper 8. Then, a silicon oxide film having a predetermined thickness is grown, and polysilicon is deposited thereon. By patterning the silicon oxide film and the polysilicon, the gate oxide film 10 and the gate electrode 11 of the charge coupled device EC are formed, and the pattern 12 of the resist material is further formed. Then, N type impurities, for example, phosphorus ions are implanted to form an N + region 9. In FIG. 2 (d), an insulating film, for example, a PSG film is deposited and a pattern 13 of the insulating film is formed by a photoresist method. After depositing a metal film, for example, a platinum film, and subjecting it to heat treatment, the Schottky diode metal electrode layer 14, for example, other than platinum silicide is removed by etching with a predetermined etching solution to complete the process.
ところで、従来のショットキ型イメージセンサの製造方
法によるときには、ショットキダイオードSDのガードリ
ング６の内側に有効受光領域を形成する工程で、Si基板
上の既存のパターンに対し、有効受光領域パターニング
のフォトレジストのための目合わせを行う必要がある。
そのため、この際に生じる目合わせズレを考慮した有効
受光領域パターンにより、パターニングを行わなければ
ならず、有効受光領域を大きくできないという欠点があ
った。By the way, according to the conventional method of manufacturing the Schottky type image sensor, in the step of forming the effective light receiving area inside the guard ring 6 of the Schottky diode SD, the photoresist for the effective light receiving area patterning is applied to the existing pattern on the Si substrate. Need to make an alignment for.
Therefore, there is a drawback that the effective light receiving area pattern cannot be enlarged because patterning must be performed by the effective light receiving area pattern in consideration of misalignment that occurs at this time.
本発明の目的は上記欠点を除去し、大きな有効受光領域
を確保したショットキ型イメージセンサの製造方法を提
供することにある。It is an object of the present invention to provide a method for manufacturing a Schottky type image sensor which eliminates the above-mentioned drawbacks and secures a large effective light receiving area.
上記目的を達成するため、本発明のショットキ型イメー
ジセンサの製造方法においては、一導電型半導体基板表
面上に第一の酸化膜を形成した後、該第一の酸化膜上に
窒化膜を成長させ、電荷結合素子活性領域上および同一
基板表面上の受光素子ガードリング上の該窒化膜を除去
し、該残留窒化膜をマスクとして該電荷結合素子活性領
域および該ガードリング用の不純物を導入し、受光素子
受光部以外の該残留窒化膜をレジスト材で被覆した後、
該受光素子受光部上の該窒化膜を除去し、前記レジスト
材を除去した後に酸化を行い、該活性領域および該受光
素子上に所定の厚さの第二の酸化膜を形成し、前記残留
窒化膜を除去し、その後前記第二の酸化膜をマスクとし
てチャネルストッパ用の不純物を導入する工程を含むこ
とを特徴とするものである。In order to achieve the above object, in the method of manufacturing a Schottky image sensor of the present invention, after forming a first oxide film on the surface of a one conductivity type semiconductor substrate, a nitride film is grown on the first oxide film. Then, the nitride film on the charge coupled device active region and the light receiving device guard ring on the surface of the same substrate is removed, and impurities for the charge coupled device active region and the guard ring are introduced using the residual nitride film as a mask. After coating the residual nitride film other than the light receiving portion of the light receiving element with a resist material,
The nitride film on the light receiving portion of the light receiving element is removed, the resist material is removed, and then oxidation is performed to form a second oxide film of a predetermined thickness on the active region and the light receiving element. The method is characterized by including a step of removing the nitride film and then introducing an impurity for a channel stopper using the second oxide film as a mask.
本発明においては、電荷結合素子活性領域形成のための
不純物の導入と、ショットキダイオードのガードリング
形成のための不純物の導入を同一パターンにより同時に
行なう。その後、ショットキダイオード中央部分の窒化
膜を除去し、これを熱酸化する。このため、従来の製造
方法で必要とされていたショットキダイオード有効受光
領域形成のために余分な目合わせマージンを考慮しなく
て済む。本発明の製造方法ではショットキダイオードガ
ードリングを必要最小面積に設計および製造することに
より、ショットキダイオード有効受光領域を大きく確保
することができる。In the present invention, the introduction of the impurity for forming the charge coupled device active region and the introduction of the impurity for forming the guard ring of the Schottky diode are simultaneously performed in the same pattern. After that, the nitride film in the central portion of the Schottky diode is removed and this is thermally oxidized. Therefore, it is not necessary to consider an extra alignment margin for forming the Schottky diode effective light receiving region, which is required in the conventional manufacturing method. In the manufacturing method of the present invention, the Schottky diode guard ring is designed and manufactured to have a required minimum area, whereby a large Schottky diode effective light receiving region can be secured.
以下に本発明の実施例を図によって説明する。 Embodiments of the present invention will be described below with reference to the drawings.
第１図（ａ）〜（ｅ）は本発明のショットキ型イメージ
センサの一実施例の主な製造工程における断面図を示し
たものである。FIGS. 1 (a) to 1 (e) are sectional views showing the main manufacturing steps of one embodiment of the Schottky type image sensor of the present invention.
第１図（ａ）において、Ｐ型Si基板１上に第１シリコン
酸化膜２、シリコン窒化膜を成長させた後、フォトレジ
スト法により窒化膜のパターン３および３′を形成す
る。しかる後、Ｎ型不純物、例えばリンをイオン注入す
る。次いで第１図（ｂ）のようにレジスト材のパターン
４を形成する。窒化膜３′を除去した後、第１図（Ｃ）
のように熱酸化を行ない、N-型CCD活性領域７とN-型ガ
ードリング６および第二酸化膜層５を形成する。Ｐ型の
不純物、例えばボロンのイオン注入を行ない、第１図
（ｄ）のように、チャネルストッパ８を形成する。所定
の厚さのシリコン酸化膜を成長し、その上にポリシリコ
ンを堆積する。該シリコン酸化膜およびポリシリコンを
パターニングすることにより、電荷結合素子ECのゲート
酸化膜10およびゲート電極11を形成し、さらにレジスト
材のパターン12を形成する。しかる後、Ｎ型不純物、例
えばリンのイオン注入を行ない、N+領域９を形成する。
絶縁膜、例えばPSG膜を堆積し、フォトレジスト法によ
り絶縁膜のパターン13を形成する。第１図（ｅ）におい
て、金属膜、例えば白金膜を堆積し、熱処理を施した
後、所定のエッチング液により、ショットキダイオード
SDの金属電極層14、例えば白金シリサイド以外をエッチ
ンゲ除去して完成する。In FIG. 1A, after a first silicon oxide film 2 and a silicon nitride film are grown on a P-type Si substrate 1, nitride film patterns 3 and 3'are formed by a photoresist method. Then, N-type impurities such as phosphorus are ion-implanted. Next, as shown in FIG. 1 (b), a resist material pattern 4 is formed. After removing the nitride film 3 ', FIG.
Thermal oxidation is performed as described above to form the N − type CCD active region 7, the N − type guard ring 6 and the second dioxide film layer 5. Ion implantation of P-type impurities such as boron is performed to form the channel stopper 8 as shown in FIG. A silicon oxide film having a predetermined thickness is grown, and polysilicon is deposited thereon. By patterning the silicon oxide film and the polysilicon, the gate oxide film 10 and the gate electrode 11 of the charge coupled device EC are formed, and the pattern 12 of the resist material is further formed. Then, N type impurities, for example, phosphorus ions are implanted to form the N + region 9.
An insulating film, for example, a PSG film is deposited and a pattern 13 of the insulating film is formed by a photoresist method. In FIG. 1 (e), a Schottky diode is formed by depositing a metal film, for example, a platinum film, heat-treating it, and then using a predetermined etching solution.
The SD metal electrode layer 14, for example, other than platinum silicide is removed by etching to complete the process.
ショットキ型イメージセンサの単位画素UEの平面図を第
３図に示す。前記第１図および第２図は第３図のＡ−
Ａ′の断面構造を製造工程毎に模式的に示したものであ
る。単位画素UEは前述した様に、電荷結合素子ECとショ
ットキダイオードSDとで構成されている。ショットキダ
イオードSDでの発生電荷量と電荷結合素子ECでの転送電
荷量とが均合うように、両者の割合を最適化して、設
計，製造されている。ショットキダイオードSDの有効受
光領域21はガードリング20の内側の領域である。イメー
ジセンサの感度を向上させるためには前記有効受光面積
を大きく確保すればよいが、そのためには耐圧の低下、
逆方向電流の増加等のエッジ効果を低減するために配し
てある前記ガードリング（参考文献:Metal−semiconduc
tor contacts E.H.RHODERICK,CLARENDONPRESS OXFORD
（1978）p.118−119）を必要最小限の面積にすることに
よりショットキダイオード有効受光面積を大きく確保す
れば良い。A plan view of the unit pixel UE of the Schottky type image sensor is shown in FIG. FIG. 1 and FIG. 2 are A- of FIG.
The cross-sectional structure of A'is schematically shown for each manufacturing process. As described above, the unit pixel UE includes the charge coupled device EC and the Schottky diode SD. The Schottky diode SD is designed and manufactured by optimizing the ratio of both so that the generated charge amount and the charge transfer amount in the charge coupled device EC are equalized. The effective light receiving area 21 of the Schottky diode SD is an area inside the guard ring 20. In order to improve the sensitivity of the image sensor, it is sufficient to secure a large effective light receiving area, but for that purpose, the breakdown voltage is lowered,
The guard ring is provided to reduce edge effects such as increase in reverse current (reference: Metal-semiconduc
tor contacts EHRHODERICK, CLARENDONPRESS OXFORD
(1978) p.118-119) should be set to the minimum necessary area to secure a large effective light receiving area for the Schottky diode.
以上のように本発明によれば、チャネルストッパと前記
ショットキダイオード有効受光領域とのパターニングを
同一マスクにより行なうため、該ガードリングを必要最
小面積に形成し、前記ショットキダイオード有効面積を
大きく確保することができる効果を有する。As described above, according to the present invention, since the patterning of the channel stopper and the Schottky diode effective light receiving region is performed by the same mask, the guard ring is formed in a necessary minimum area to secure a large Schottky diode effective area. It has the effect that
【図面の簡単な説明】 第１図（ａ）〜（ｅ）は本発明の一実施例を工程順に示
す断面模式図、第２図（ａ）〜（ｄ）は従来の製造方法
の一例を工程順に示す断面模式図、第３図は典型的なシ
ョットキ型イメージセンサの平面図である。 １……Ｐ型Si基板、２……第１シリコン酸化膜 3,3′……窒化膜のパターン 4,12……レジスト材のパターン ５……第二酸化膜層、６……ガードリング ７……電荷結合素子（N-型CCD）活性領域 ８……チャネルストッパ、９……N+領域 10……ゲート酸化膜、11……ゲート電極 13……絶縁膜のパターン 14……ショットキダイオード金属電極層BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) to (e) are schematic sectional views showing an embodiment of the present invention in the order of steps, and FIGS. 2 (a) to (d) are examples of conventional manufacturing methods. FIG. 3 is a schematic sectional view showing the order of steps, and FIG. 3 is a plan view of a typical Schottky image sensor. 1 ... P-type Si substrate, 2 ... first silicon oxide film 3,3 '... nitride film pattern 4,12 ... resist material pattern 5 ... dioxide film layer, 6 ... guard ring 7 ... Charge-coupled device (N - type CCD) active region 8 ... Channel stopper, 9 ... N + region 10 ... Gate oxide film, 11 ... Gate electrode 13 ... Insulating film pattern 14 ... Schottky diode metal electrode layer
Claims (1)
を形成した後、該第一の酸化膜上に窒化膜を成長させ、
電荷結合素子活性領域上および同一基板表面上の受光素
子ガードリング上の該窒化膜を除去し、該残留窒化膜を
マスクとして該電荷結合素子活性領域および該ガードリ
ング用の不純物を導入し、受光素子受光部以外の該残留
窒化膜をレジスト材で被覆した後、該受光素子受光部上
の該窒化膜を除去し、前記レジスト材を除去した後に酸
化を行い、該活性領域および該受光素子上に所定の厚さ
の第二の酸化膜を形成し、前記残留窒化膜を除去し、そ
の後前記第二の酸化膜をマスクとしてチャネルストッパ
用の不純物を導入する工程を含むことを特徴とするショ
ットキ型イメージセンサの製造方法。1. A first oxide film is formed on the surface of a semiconductor substrate of one conductivity type, and a nitride film is grown on the first oxide film.
The nitride film on the charge coupled device active region and the light receiving device guard ring on the same substrate surface is removed, and impurities for the charge coupled device active region and the guard ring are introduced using the residual nitride film as a mask to receive light. After coating the residual nitride film other than the light receiving portion of the element with a resist material, the nitride film on the light receiving portion of the light receiving element is removed, and after the resist material is removed, oxidation is performed to remove the nitride film on the active region and the light receiving element. A second oxide film having a predetermined thickness, a step of removing the residual nitride film, and then introducing an impurity for a channel stopper using the second oxide film as a mask. Type image sensor manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63108636A JPH07120776B2 (en) | 1988-04-28 | 1988-04-28 | Schottky type image sensor manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63108636A JPH07120776B2 (en) | 1988-04-28 | 1988-04-28 | Schottky type image sensor manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01278067A JPH01278067A (en) | 1989-11-08 |
| JPH07120776B2 true JPH07120776B2 (en) | 1995-12-20 |
Family
ID=14489821
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63108636A Expired - Fee Related JPH07120776B2 (en) | 1988-04-28 | 1988-04-28 | Schottky type image sensor manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07120776B2 (en) |
-
1988
- 1988-04-28 JP JP63108636A patent/JPH07120776B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01278067A (en) | 1989-11-08 |
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