JP2574304B2 - Method for manufacturing solid-state imaging device - Google Patents
Method for manufacturing solid-state imaging deviceInfo
- Publication number
- JP2574304B2 JP2574304B2 JP62154749A JP15474987A JP2574304B2 JP 2574304 B2 JP2574304 B2 JP 2574304B2 JP 62154749 A JP62154749 A JP 62154749A JP 15474987 A JP15474987 A JP 15474987A JP 2574304 B2 JP2574304 B2 JP 2574304B2
- Authority
- JP
- Japan
- Prior art keywords
- state imaging
- photoelectric conversion
- imaging device
- conversion element
- shift register
- 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 - Lifetime
Links
- 238000003384 imaging method Methods 0.000 title claims description 9
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 238000000034 method Methods 0.000 title claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 10
- 239000012535 impurity Substances 0.000 claims description 10
- 239000000758 substrate Substances 0.000 claims description 8
- 239000004065 semiconductor Substances 0.000 claims description 5
- 230000003287 optical effect Effects 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims 1
- 206010047571 Visual impairment Diseases 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000005684 electric field Effects 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
- -1 boron ions Chemical class 0.000 description 1
- 230000000779 depleting effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Landscapes
- Solid State Image Pick-Up Elements (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、固体撮像装置の製造方法に関するものであ
る。Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a solid-state imaging device.
従来の技術 CCD型固体撮像装置、特にインターラインCCD固体撮像
装置は総合特性がすぐれているため、実用化が進んでい
る。特性の中で、重要なものの１つに残像がある。そし
て残像特性として特に問題とされているのは低照度にお
ける残像である。この残像は光電変換素子［以下フォト
ダイオード（PD）とよぶ］の構造で決定される。従来、
PN接合を有するPDでは、光信号を蓄積する不純物領域を
完全空乏化することによりこの残像を制御していた。2. Description of the Related Art CCD-type solid-state imaging devices, particularly interline CCD solid-state imaging devices, have excellent overall characteristics and are being put to practical use. One of the important characteristics is an afterimage. A particularly problematic afterimage characteristic is an afterimage at low illuminance. This afterimage is determined by the structure of the photoelectric conversion element [hereinafter referred to as a photodiode (PD)]. Conventionally,
In a PD having a PN junction, the afterimage is controlled by completely depleting an impurity region for storing an optical signal.
発明が解決しようとする問題点 しかしながら残像特性は高水準で安定させなければな
らず、単にPDの不純物領域を完全空乏化するだけでは不
十分である。Problems to be Solved by the Invention However, the afterimage characteristics must be stabilized at a high level, and it is not sufficient to simply completely deplete the impurity region of the PD.
本発明の目的は、従来の欠点を解消し、残像特性を向
上させるとともに、安定に製造できる固体撮像装置の製
造方法を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a solid-state imaging device which can solve the conventional disadvantages, improve after-image characteristics, and can be manufactured stably.
問題点を解決するための手段 本発明の固体撮像装置の製造方法は、垂直走査用CDD
シフトレジスタ側とは反対側の前記光電変換素子近傍に
半導体基板と同一導電形の不純物を狭い幅で選択的に導
入し、前記光電変換素子の不純物濃度を前記垂直走査用
CCDシフトレジスタ側に向かって高くするようにしたも
のである。Means for Solving the Problems The method for manufacturing a solid-state imaging device according to the present invention includes a vertical scanning CDD.
An impurity of the same conductivity type as that of the semiconductor substrate is selectively introduced in a narrow width in the vicinity of the photoelectric conversion element on the side opposite to the shift register side, and the impurity concentration of the photoelectric conversion element is adjusted for the vertical scanning.
The height is increased toward the CCD shift register.
作用 上記の製造方法により、光電変換素子の近傍に導入さ
れた不純物により光電変換素子の濃度が、前記不純物を
導入した側では大きく打ち消され低くなり、光電変換素
子内に垂直走査用CCDシフトレジスタ側が深くなるポテ
ンシャル分布が形成される。According to the above-described manufacturing method, the concentration of the photoelectric conversion element due to the impurity introduced in the vicinity of the photoelectric conversion element is largely canceled and lowered on the side where the impurity is introduced, and the vertical scanning CCD shift register side is located in the photoelectric conversion element. A deeper potential distribution is formed.
実施例 図は、本発明の一実施例による固体撮像装置の製造方
法を示す断面図である。Embodiment FIG. 4 is a cross-sectional view illustrating a method for manufacturing a solid-state imaging device according to an embodiment of the present invention.
図に示す構造を得るために、まずｐ形シリコン基板１
に、選択的に図示したＡの矢印の場所に２μｍ以下の幅
で帯状にボロンイオン注入を行ないｐ形領域２を形成す
る。注入量は約1012cm-2である。拡散長が次に形成する
PDとなるｎ形領域３の約中程までとなるように最終工程
までの熱履歴を考慮して適当なドライブインを行う。そ
して前述した様に、ｎ形領域３を形成し、CCD埋込みチ
ャンネル４を形成後、垂直走査用CCDシフトレジスタ電
極５を形成する。なお、この場合、ｎ形領域３とCCD埋
込みチャンネル４の形成順序は特に問題とせず、順序が
逆でも、また同時でもかまわない。ｐ形領域２を形成す
るに必要な矢印Ａへのボロンイオン注入幅は、ｎ形領域
３の幅に対して1/3から1/10となるようにする。その結
果、２μｍ以下となる。そのためｐ形領域２の濃度分布
形成は、断面では破線で示したような同心半円に近いも
のとなる。ｎ形領域３は、前記同心半円の片側の領域に
形成されるため、図に示すように、CDシフトレジスタ側
（すなわち信号読出し側）が最も深くなる。このような
形状のｎ形領域３が出来ると必然的に、PDのポテンシャ
ル形状は、不純物形状にそったものとなるため、信号読
出し側が最も深いポテンシャルとなり、読出し側から離
れるにしたがってポテンシャルは浅く形成される。よっ
て、信号電荷は、PD内に形成された電界により加速さ
れ、残像電荷が残らないとともに従来に比べてさらに読
出し速度が向上する。In order to obtain the structure shown in FIG.
Then, boron ions are selectively implanted in a band shape having a width of 2 μm or less at a location indicated by an arrow A in the drawing to form a p-type region 2. The injection volume is about 10 12 cm -2 . Diffusion length forms next
Appropriate drive-in is performed in consideration of the heat history up to the final process so that the n-type region 3 serving as a PD is approximately in the middle. Then, as described above, after the n-type region 3 is formed and the CCD buried channel 4 is formed, the vertical scan CCD shift register electrode 5 is formed. In this case, the order of forming the n-type region 3 and the CCD buried channel 4 does not matter, and the order may be reversed or simultaneous. The boron ion implantation width to the arrow A necessary for forming the p-type region 2 is set to be 1/3 to 1/10 of the width of the n-type region 3. As a result, it becomes 2 μm or less. Therefore, the formation of the concentration distribution of the p-type region 2 is close to a concentric semicircle as shown by the broken line in the cross section. Since the n-type region 3 is formed on one side of the concentric semicircle, the CD shift register side (that is, the signal reading side) is deepest as shown in the figure. When the n-type region 3 having such a shape is formed, the potential shape of the PD necessarily follows the impurity shape, so that the signal read side has the deepest potential, and the potential becomes shallower as the distance from the read side increases. Is done. Therefore, the signal charges are accelerated by the electric field formed in the PD, so that the afterimage charges do not remain and the reading speed is further improved as compared with the related art.
なお、本発明の一実施例は出発材料をｐ形シリコン基
板としたが、ｎ形シリコン基板上に形成されたｐ形ウエ
ルにおいても有効であることは明白である。Although the p-type silicon substrate is used as a starting material in the embodiment of the present invention, it is apparent that the present invention is also effective for a p-type well formed on an n-type silicon substrate.
また、本発明によるものは、PDとなるｎ形領域３がPD
に電界を発生させるｐ形領域２の少なくとも片側の領域
にあればよく、マスク合せ精度も厳密なものは必要とせ
ずプロセスの変動に影響されない。Also, according to the present invention, the n-type region 3 serving as a PD is a PD.
It is sufficient that the mask is positioned at least on one side of the p-type region 2 where an electric field is generated, and the mask alignment accuracy does not need to be strict, and is not affected by process variations.
発明の効果 以上のように本発明によれば、PD内の信号電荷読出し
速度を向上させるとともに残像特性を向上させ、しかも
その製造方法は、従来からの製造方法を用い、しかも特
性のばらつきを十分低く押える効果があるなど、その実
用的効果は大なるものがある。Effects of the Invention As described above, according to the present invention, the signal charge reading speed in the PD is improved and the afterimage characteristic is improved. The practical effect is great, such as the effect of holding down.
図は本発明の一実施例の断面図である。 １……ｐ形シリコン基板、２……ｐ形領域、３……ｎ形
領域、４……CCD埋込みチャンネル、５……垂直走査用C
CDシフトレジスタ電極。FIG. 1 is a sectional view of one embodiment of the present invention. 1 ... p-type silicon substrate, 2 ... p-type region, 3 ... n-type region, 4 ... CCD embedded channel, 5 ... C for vertical scanning
CD shift register electrode.
Claims (1)
半導体基板とは逆導電形の不純物よりなる光電変換素子
領域と、前期光電変換素子領域から光信号を読み出し転
送するCCDシフトレジスタを備えた固体撮像装置の製造
方法において、前記CCDシフトレジスタ側とは反対側の
前記光電変換素子領域近傍の半導体基板表面に、前記半
導体基板と同導電形の不純物を選択的に導入し、その後
さらに熱処理することにより、前記光電変換素子領域内
の逆導電形の不純物濃度を前記CCDシフトレジスタ側に
向かって高くすることを特徴とする固体撮像装置の製造
方法。1. A photoelectric conversion element region formed on a surface of a semiconductor substrate of one conductivity type and made of impurities of a conductivity type opposite to that of the semiconductor substrate, and a CCD shift register for reading and transferring an optical signal from the photoelectric conversion element region. In the method of manufacturing a solid-state imaging device provided, the semiconductor substrate surface near the photoelectric conversion element region on the opposite side to the CCD shift register side, selectively introduces impurities of the same conductivity type as the semiconductor substrate, and then further A method for manufacturing a solid-state imaging device, wherein heat treatment is performed to increase the impurity concentration of the opposite conductivity type in the photoelectric conversion element region toward the CCD shift register.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62154749A JP2574304B2 (en) | 1987-06-22 | 1987-06-22 | Method for manufacturing solid-state imaging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62154749A JP2574304B2 (en) | 1987-06-22 | 1987-06-22 | Method for manufacturing solid-state imaging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63318771A JPS63318771A (en) | 1988-12-27 |
| JP2574304B2 true JP2574304B2 (en) | 1997-01-22 |
Family
ID=15591071
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62154749A Expired - Lifetime JP2574304B2 (en) | 1987-06-22 | 1987-06-22 | Method for manufacturing solid-state imaging device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2574304B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5437422A (en) * | 1977-08-29 | 1979-03-19 | Toshiba Corp | Solid state pickup device |
| JPS61248554A (en) * | 1985-04-26 | 1986-11-05 | Mitsubishi Electric Corp | Solid-state image pickup element and manufacture thereof |
-
1987
- 1987-06-22 JP JP62154749A patent/JP2574304B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63318771A (en) | 1988-12-27 |
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