JPH09162137A - Ion implantation - Google Patents
Ion implantationInfo
- Publication number
- JPH09162137A JPH09162137A JP7346771A JP34677195A JPH09162137A JP H09162137 A JPH09162137 A JP H09162137A JP 7346771 A JP7346771 A JP 7346771A JP 34677195 A JP34677195 A JP 34677195A JP H09162137 A JPH09162137 A JP H09162137A
- Authority
- JP
- Japan
- Prior art keywords
- ion implantation
- photoresist layer
- opening
- mask pattern
- mask
- 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.)
- Granted
Links
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- Photosensitive Polymer And Photoresist Processing (AREA)
- Physical Vapour Deposition (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、イオン注入方法に
関し、更に詳細にはイオン注入領域の位置及び面積を微
細に調整できるイオン注入方法、特にＣＣＤ撮像素子の
垂直転送部の形成に適したイオン注入方法に関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation method, and more particularly to an ion implantation method capable of finely adjusting the position and area of an ion implantation region, and more particularly, an ion suitable for forming a vertical transfer portion of a CCD image pickup device. It concerns the injection method.
【０００２】[0002]
【従来の技術】一般に、基板にイオンを注入してイオン
注入領域を形成する際、イオン注入は、ポリシリコン、
ＳｉＯ2 などのデバイス構成材料やホトレジスト等で形
成されるマスクパターンの上から基板に向け施され、こ
れによりパターンで定められた開口の位置及び面積に合
致するようにイオン注入領域が形成されている。従っ
て、イオン注入領域を所定通りの位置及び面積で基板に
形成するためには、ホトリソグラフィ法等で形成するマ
スクパターンの精度を高める必要がある。ホトリソグラ
フィ法でマスクパターンを形成する際、マスクパターン
の精度を決める因子は、使用する光学装置の作動精度、
例えばフォトリソグラフィステッパーの作動精度であっ
て、特に、フォトリソグラフィステッパーのショット毎
に移動する機械的精度である。従来、マスクパターンの
開口の精度、従ってイオン注入領域の位置及び面積は、
フォトリソグラフィステッパーの作動精度の限界から、
０．１μm 以下の単位で微細に調整することは困難であ
った。2. Description of the Related Art Generally, when forming an ion implantation region by implanting ions into a substrate, the ion implantation is polysilicon,
It is applied to the substrate from above a mask pattern formed of a device constituent material such as SiO 2 or photoresist, thereby forming an ion implantation region so as to match the position and area of the opening defined by the pattern. . Therefore, in order to form the ion implantation region on the substrate at a predetermined position and area, it is necessary to improve the accuracy of the mask pattern formed by the photolithography method or the like. When forming a mask pattern by photolithography, the factors that determine the accuracy of the mask pattern are the operating accuracy of the optical device used,
For example, the operation accuracy of the photolithography stepper, and in particular, the mechanical accuracy of movement of each photolithography stepper shot. Conventionally, the accuracy of the opening of the mask pattern, and hence the position and area of the ion implantation region, are
Due to the limit of operating accuracy of photolithography stepper,
It was difficult to finely adjust in units of 0.1 μm or less.
【０００３】[0003]
【発明が解決しようとする課題】ところで、半導体デバ
イスの微細化に伴い、イオン注入領域の位置及び面積を
０．１μm 単位で制御する必要が生じて来ている。ここ
で、ＣＣＤ撮像素子を例にしてイオン注入領域の位置及
び面積の調整の必要性を説明する。最近のＣＣＤ撮像素
子では、単セル分離部（画素分離部）幅や蓄積電荷読み
出し部幅が、マスク上で０．４〜０．７μｍ程度にまで
縮小されており、また転送部幅も１μｍ程度になってい
る。従って、ＣＣＤ撮像素子において、蓄積・転送電荷
量を確保しつつ電場強度を緩和するためには、垂直転送
部を形成するイオン注入領域の位置及び面積を０．１μ
ｍ単位で調整することが必要である。By the way, with the miniaturization of semiconductor devices, it has become necessary to control the position and area of the ion implantation region in units of 0.1 μm. Here, the necessity of adjusting the position and area of the ion implantation region will be described by taking the CCD image pickup device as an example. In the recent CCD image pickup device, the width of the single cell separation portion (pixel separation portion) and the width of the accumulated charge reading portion are reduced to about 0.4 to 0.7 μm on the mask, and the width of the transfer portion is also about 1 μm. It has become. Therefore, in the CCD image pickup device, in order to reduce the electric field strength while securing the amount of accumulated / transferred charges, the position and area of the ion implantation region forming the vertical transfer portion are set to 0.1 μm.
It is necessary to adjust in m units.
【０００４】図６から図８を参照しつつ、垂直転送部形
成のための従来のイオン注入方法を説明する。図６は、
垂直転送部形成のためのイオン注入が従来の方法で行わ
れたＣＣＤ撮像素子の有効画素の積層構造１０を示す断
面図である。図６中、１１はＳｉ基板、１２はｐ- 型の
オーバーフローバリア層、１３は絶縁膜、２１はｐ-ウ
エルからなる転送バリア部、２２はｎ型の垂直転送部、
２３はｐ- 型の読み出しバリア部、２４はｎ型の受光
部、２５はｐ+ 型のホール蓄積部、２６はチャネルスト
ップ、３１はポリシリコンからなる転送電極、３２はポ
リシリコン酸化膜からなる絶縁膜、３３はＰＳＧ等のパ
ッシベーション膜及び３４はＡｌからなる遮光膜であ
る。図６は、更に、基板表面の絶縁膜１３の下側界面か
ら約０．２〜０．３μｍ深さに位置する水平方向断面３
５に沿ったポテンシャルの電位を示している。断面３５
から下向きに＋電位が取ってあり、電子にとっては上に
凸のポテンシャルがバリアとなる。A conventional ion implantation method for forming a vertical transfer portion will be described with reference to FIGS. 6 to 8. FIG.
FIG. 11 is a cross-sectional view showing a laminated structure 10 of effective pixels of a CCD image pickup device in which ion implantation for forming a vertical transfer portion is performed by a conventional method. In FIG. 6, 11 is a Si substrate, 12 is a p − type overflow barrier layer, 13 is an insulating film, 21 is a transfer barrier part formed of a p − well, 22 is an n type vertical transfer part,
Reference numeral 23 is a p - type read barrier portion, 24 is an n-type light receiving portion, 25 is a p + type hole accumulation portion, 26 is a channel stop, 31 is a transfer electrode made of polysilicon, and 32 is a polysilicon oxide film. An insulating film, 33 is a passivation film such as PSG, and 34 is a light shielding film made of Al. FIG. 6 further shows a horizontal cross section 3 located at a depth of about 0.2 to 0.3 μm from the lower interface of the insulating film 13 on the substrate surface.
The potential of the potential along 5 is shown. Cross section 35
+ Potential is taken downward from, and the upward convex potential becomes a barrier for electrons.
【０００５】従来、垂直転送部を形成するために、先
ず、基板１１上に、図７に示すように、ホトレジスト層
４０を成膜する。図７中、１２はオーバーフローバリア
層１２、及び１３は酸化絶縁膜である。次いで、フォト
レジスト層４０をｇ線，ｉ線，エキシマレーザーなどの
光で露光し、現像して、所望のパターンを形成し、これ
をマスクとして第１次イオン注入及び第２次イオン注入
を連続して行い、続いて熱処理を施し、注入した不純物
イオンを拡散させている。第１次イオン注入により転送
バリア部２１を、第２次イオン注入により垂直転送部２
２をそれぞれ形成している。イオン注入工程の後、引き
続き、転送電極３１、ホール蓄積部２５、受光部２４及
びポリシリコン酸化膜３２を形成し、図８に示すような
積層構造を得る。更に、ＰＳＧ等のパッシベーション膜
３３及びＡｌの遮光膜３４を形成すると、図６に示すよ
うな積層構造１０を備えたＣＣＤ撮像素子有効画素を得
ることができる。Conventionally, in order to form a vertical transfer portion, first, a photoresist layer 40 is formed on the substrate 11 as shown in FIG. In FIG. 7, 12 is an overflow barrier layer 12 and 13 is an oxide insulating film. Then, the photoresist layer 40 is exposed to light such as g-line, i-line, and excimer laser, and developed to form a desired pattern. Using this as a mask, primary ion implantation and secondary ion implantation are continuously performed. Then, heat treatment is performed to diffuse the implanted impurity ions. The transfer barrier portion 21 is formed by the primary ion implantation, and the vertical transfer portion 2 is formed by the secondary ion implantation.
2 are formed respectively. After the ion implantation step, the transfer electrode 31, the hole accumulating portion 25, the light receiving portion 24 and the polysilicon oxide film 32 are continuously formed to obtain a laminated structure as shown in FIG. Further, by forming the passivation film 33 such as PSG and the light shielding film 34 of Al, it is possible to obtain a CCD image sensor effective pixel having the laminated structure 10 as shown in FIG.
【０００６】ところで、蓄積・転送電荷量を確保しつつ
電場強度を緩和するためには、垂直転送部下層２１及び
垂直転送部上層２２を形成する際に、垂直転送部２２の
幅を転送バリア部２１より僅かに小さくして、垂直転送
部２２を転送バリア部２１により包み込むような形にす
ることが有効である。しかし、従来の方法では、同じマ
スクパターンを使用して転送バリア部２１及び垂直転送
部２２を形成しているので、第２次イオン注入により形
成した垂直転送部の幅と第１次イオン注入により形成し
た転送バリア部の幅とは、図７に示すように、殆ど同じ
になる。By the way, in order to reduce the electric field strength while securing the amount of accumulated / transferred charges, the width of the vertical transfer portion 22 is set to the width of the transfer barrier portion when the vertical transfer portion lower layer 21 and the vertical transfer portion upper layer 22 are formed. It is effective to make the vertical transfer section 22 slightly smaller than 21 so that the vertical transfer section 22 is surrounded by the transfer barrier section 21. However, in the conventional method, since the transfer barrier portion 21 and the vertical transfer portion 22 are formed using the same mask pattern, the width of the vertical transfer portion formed by the secondary ion implantation and the primary ion implantation are The width of the formed transfer barrier portion is almost the same as shown in FIG.
【０００７】そこで、転送バリア部２１を形成する第１
次イオン注入の際のマスクパターンの開口径より僅かに
小さい開口径のマスクパターンを形成して第２次イオン
注入を行って転送バリア部２１の幅より狭い垂直転送部
２２を形成しようとしても、上述したように、このよう
な高精度のマスク合わせを可能にするように、ホトリソ
グラフィ法で使用する装置の作動精度を高めることは難
しい。従って、ステッパーの位置合わせ精度の限界か
ら、通常、０．１μｍ程度のズレが発生するため、所望
のマスクパターンを得ることはできない。また、注入イ
オンの拡散を制御して垂直転送部の幅を調整しようとし
ても、それは技術的に難しく、注入する不純物元素の種
類により熱拡散係数が異なるため、垂直転送部２２の幅
は、転送バリア部２１の幅に対して僅かに異なるもの
の、イオン注入時に同一パターンを使用している限り、
基本的には深さ方向にしか自由度が無いことが判る。Therefore, the first to form the transfer barrier portion 21
Even if an attempt is made to form a mask pattern having an opening diameter slightly smaller than the opening diameter of the mask pattern at the time of secondary ion implantation and perform secondary ion implantation to form a vertical transfer portion 22 narrower than the width of the transfer barrier portion 21, As described above, it is difficult to increase the operating accuracy of the apparatus used in the photolithography method so as to enable such highly accurate mask alignment. Therefore, due to the limit of the positioning accuracy of the stepper, a deviation of about 0.1 μm is usually generated, and a desired mask pattern cannot be obtained. Even if it is attempted to control the diffusion of implanted ions to adjust the width of the vertical transfer portion, it is technically difficult and the thermal diffusion coefficient varies depending on the type of the impurity element to be implanted. Although slightly different from the width of the barrier portion 21, as long as the same pattern is used during ion implantation,
It can be seen that there is basically only freedom in the depth direction.
【０００８】以上、説明したように、従来の方法では、
イオン注入領域の位置及び面積を微細に調整できるよう
なマスクパターンを得ることは難しい。そこで、本発明
の目的は、イオン注入に際し、マスクパターンの開口の
位置及び面積を微細に調整する方法を提供することであ
る。As described above, according to the conventional method,
It is difficult to obtain a mask pattern in which the position and area of the ion implantation region can be finely adjusted. Therefore, an object of the present invention is to provide a method for finely adjusting the position and area of the opening of the mask pattern during ion implantation.
【０００９】[0009]
【課題を解決するための手段】上記目的を達成するため
に、本発明に係るイオン注入方法は、基板上にホトレジ
スト層からなるマスクパターンを形成し、ホトレジスト
層をマスクにしてイオン注入する際、ホトレジスト層に
リフロー熱処理を施して、マスクパターンの開口部の下
端縁の開口径を縮小させ、それによってイオン注入領域
の位置及び面積を調整することを特徴としている。In order to achieve the above object, an ion implantation method according to the present invention comprises a step of forming a mask pattern made of a photoresist layer on a substrate and performing ion implantation using the photoresist layer as a mask. The photoresist layer is subjected to reflow heat treatment to reduce the opening diameter of the lower end edge of the opening of the mask pattern, thereby adjusting the position and area of the ion implantation region.
【００１０】リフロー熱処理の条件は、縮小させる割
合、使用するホトレジストの種類、マスクパターンの開
口の大きさ等により異なり、実績、実験等により決定す
る。The conditions of the reflow heat treatment differ depending on the reduction ratio, the type of photoresist used, the size of the opening of the mask pattern, etc., and are determined by actual results, experiments, etc.
【００１１】本発明に係るイオン注入方法は、特にＣＣ
Ｄ撮像素子の垂直転送部の形成に適している。本発明に
係るイオン注入方法は、ＣＣＤ撮像素子の垂直転送部の
形成工程で、基板の絶縁膜上にホトレジスト層からなる
マスクパターンを形成し、ホトレジスト層をマスクにし
てイオン注入により転送バリア部を形成し、次いで別の
イオンを注入して垂直転送部を形成するに当たり、ホト
レジスト層にリフロー熱処理を施して、マスクパターン
の開口部の下端縁の開口径を縮小させ、それによって垂
直転送部を形成するイオン注入領域の位置及び面積を調
整することを特徴としている。The ion implantation method according to the present invention is particularly applicable to CC
It is suitable for forming the vertical transfer portion of the D image pickup device. According to the ion implantation method of the present invention, a mask pattern made of a photoresist layer is formed on an insulating film of a substrate in a step of forming a vertical transfer portion of a CCD image sensor, and a transfer barrier portion is formed by ion implantation using the photoresist layer as a mask. In forming the vertical transfer part by forming another ion after forming the same, the photoresist layer is subjected to reflow heat treatment to reduce the opening diameter of the lower edge of the mask pattern opening, thereby forming the vertical transfer part. The feature is that the position and the area of the ion implantation region are adjusted.
【００１２】[0012]
【発明の実施の形態】以下に、実施例を挙げ、添付図面
を参照して、本発明の実施の形態を具体的かつ詳細に説
明する。図１は本発明方法で形成したＣＣＤ撮像素子有
効画素の積層構造のＨ方向断面図、図２から図５は図１
の積層構造の形成に本発明方法を適用した場合のＣＣＤ
撮像素子有効画素の各工程毎のＨ方向断面図である。本
発明方法では、従来の方法と同様にして、先ず、イオン
注入によりＳｉ基板１１にｐ- 型のオーバーフローバリ
ア層１２を形成し、次いで熱酸化により絶縁膜１３を成
膜する。続いて、開口部４２を有するマスクパターンを
ホトレジスト層４０によってホトリソグラフィ法により
形成し、次いで、図２に示すように、ホトレジスト層４
０をマスクにしてイオン注入によりｐ- ウエルからなる
転送バリア部２１を形成する。Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view in the H direction of a laminated structure of effective pixels of a CCD image pickup device formed by the method of the present invention, and FIGS.
CCD when the method of the present invention is applied to the formation of the laminated structure of
It is a H-direction sectional drawing in each process of an image sensor effective pixel. In the method of the present invention, similarly to the conventional method, first, the p − type overflow barrier layer 12 is formed on the Si substrate 11 by ion implantation, and then the insulating film 13 is formed by thermal oxidation. Subsequently, a mask pattern having the opening 42 is formed by the photoresist layer 40 by the photolithography method, and then, as shown in FIG.
A transfer barrier portion 21 composed of a p - well is formed by ion implantation using 0 as a mask.
【００１３】次に、ホトレジスト層４０にリフロー熱処
理を施して、開口部４２の下端部４４周りのホトレジス
ト層４０を流動化し、それにより、図３に示すように下
端部４４の端縁４６の開口径を縮小させる。リフロー熱
処理の条件は、使用するホトレジストの種類に異なる
が、例えばｉ線用ポジレジストを使用して、厚さを１〜
２μm のマスクパターンを形成する場合には、基板を１
〜１０分の間１００〜１５０℃の範囲の温度に維持する
ことによりリフロー熱処理を施すことが出来る。また、
適用パターンの開口幅は１μｍ程度が効果的である。Next, the photoresist layer 40 is subjected to a reflow heat treatment to fluidize the photoresist layer 40 around the lower end 44 of the opening 42, thereby opening the edge 46 of the lower end 44 as shown in FIG. Reduce the caliber. The conditions of the reflow heat treatment differ depending on the type of photoresist used, but for example, a positive resist for i-line is used and the thickness is set to 1 to
When forming a 2 μm mask pattern, use 1
Reflow heat treatment can be performed by maintaining the temperature in the range of 100 to 150 ° C. for 10 minutes. Also,
It is effective that the opening width of the applied pattern is about 1 μm.
【００１４】次に、開口径を縮小させたマスクパターン
を有するホトレジスト層４０をマスクにして、垂直転送
部２２を形成するためのイオン注入を行う。この結果、
図４に示すように、転送バリア部２１より幅の狭い垂直
転送部２２を形成することができる。引き続き、従来の
方法と同様にして、転送電極３１、ホール蓄積部２５、
受光部２４及びポリシリコン酸化膜３２を形成し、図４
に示すような積層構造を得る。更に、従来の方法と同様
にして、ＰＳＧ等のパッシベーション膜３３及びＡｌの
遮光膜３４を形成すると、図１に示すような積層構造４
８を備えたＣＣＤ撮像素子有効画素を得ることができ
る。Next, using the photoresist layer 40 having a mask pattern with a reduced opening diameter as a mask, ion implantation for forming the vertical transfer portion 22 is performed. As a result,
As shown in FIG. 4, it is possible to form the vertical transfer portion 22 having a width narrower than that of the transfer barrier portion 21. Subsequently, in the same manner as the conventional method, the transfer electrode 31, the hole accumulating portion 25,
The light receiving portion 24 and the polysilicon oxide film 32 are formed, and
A laminated structure as shown in is obtained. Further, when the passivation film 33 such as PSG and the light shielding film 34 of Al are formed in the same manner as the conventional method, the laminated structure 4 as shown in FIG.
It is possible to obtain effective pixels of the CCD image pickup device including the CCD 8.
【００１５】ホール蓄積部２５の蓄積電荷の読み出し特
性は、読み出し部２３の幅、不純物濃度、並びに転送バ
リア部２１、垂直転送部２２、受光部２４、及びホール
蓄積部２５等のホール蓄積部２５の周辺のポテンシャル
により決定される。本発明方法により形成した積層構造
４８の基板表面の絶縁膜１３の下側界面から約０．２〜
０．３μｍ深さに位置する水平方向断面３５に沿ったポ
テンシャルは、図１に示す通りである。図１では、断面
３５から下向きに＋電位が取ってある。尚、図１の一点
鎖線は、図６の一点鎖線と一致する位置に延びている。The read characteristics of the charges accumulated in the hole accumulating section 25 are as follows: width of the reading section 23, impurity concentration, and hole accumulating section 25 such as the transfer barrier section 21, the vertical transfer section 22, the light receiving section 24, and the hole accumulating section 25. It is determined by the potential around. From the lower interface of the insulating film 13 on the substrate surface of the laminated structure 48 formed by the method of the present invention, about 0.2 to
The potential along the horizontal cross section 35 located at a depth of 0.3 μm is as shown in FIG. In FIG. 1, the + potential is taken downward from the cross section 35. Note that the alternate long and short dash line in FIG. 1 extends to a position that coincides with the alternate long and short dash line in FIG.
【００１６】本発明方法で作製した図１に示すＣＣＤ撮
像素子の積層構造４８は、従来の方法で作製した図６に
示すＣＣＤ撮像素子の積層構造１０と比較して、垂直転
送部２１の水平方向（以下、Ｈ方向と略記）幅が小さ
く、ｐ−ウェルからなる転送バリア部２２によって包む
ように形成されている。しかも、転送バリア部２２が読
み出し部２３やチャンネルストップ２６と連続している
ので、転送バリア部２２は、読み出し部２３を実効的に
幅広くかつ不純物濃度を高くし、更には同様にチャンネ
ルストップ２６を幅広くかつ不純物濃度を高くするか、
濃度勾配を緩和するかすることができる。よって、本実
施例では、図１に示すように、読み出し部２３およびチ
ャンネルストップ２６のポテンシャルピーク位置が、従
来の方法により作製した図６に示す積層構造１０に比べ
て、受光部２４より垂直転送部２２の近くに位置してい
る。それにより、ポテンシャルスロープが受光部２４側
に長くなって、読み出し部２３に入射した光が光電変換
して発生した電子は、容易に受光部２４側へ移動するこ
とができるので、スミア量が減り、また感度が向上す
る。The laminated structure 48 of the CCD image pickup device shown in FIG. 1 manufactured by the method of the present invention is more horizontal than the laminated structure 10 of the CCD image pickup device shown in FIG. 6 manufactured by the conventional method. The width in the direction (hereinafter, abbreviated as the H direction) is small, and is formed so as to be surrounded by the transfer barrier portion 22 formed of the p-well. Moreover, since the transfer barrier section 22 is continuous with the read section 23 and the channel stop 26, the transfer barrier section 22 effectively widens the read section 23 and increases the impurity concentration, and further, similarly, the channel stop 26 is removed. Wider and higher impurity concentration,
The concentration gradient can be relaxed. Therefore, in this embodiment, as shown in FIG. 1, the potential peak positions of the read section 23 and the channel stop 26 are more vertically transferred from the light receiving section 24 than in the laminated structure 10 shown in FIG. 6 manufactured by the conventional method. It is located near the section 22. As a result, the potential slope becomes longer on the side of the light receiving unit 24, and the electrons generated by photoelectric conversion of the light incident on the reading unit 23 can easily move to the side of the light receiving unit 24, reducing the amount of smear. Also, the sensitivity is improved.
【００１７】また、垂直転送部２２と読み出し部２３と
の境界、垂直転送部２２とチャンネルストップ２６との
界面において、垂直転送部２２の不純物濃度勾配が、従
来の方法により作製した図６に示す積層構造１０に比べ
て、緩やかに出来るため、電場強度が低減され、熱励起
で湧き出す電子・ホールが減少するので、それが発生原
因となるノイズが低減され、また結晶欠陥が発生原因と
なる白線縦筋ノイズが低減される。Further, the impurity concentration gradient of the vertical transfer portion 22 at the boundary between the vertical transfer portion 22 and the reading portion 23 and at the interface between the vertical transfer portion 22 and the channel stop 26 is shown in FIG. As compared with the laminated structure 10, since it can be made more gradual, the electric field strength is reduced, and the electrons and holes that spring out due to thermal excitation are reduced, so that the noise that causes it is reduced, and also crystal defects occur. White line vertical stripe noise is reduced.
【００１８】以上のように、本発明方法によれば、ホト
レジスト層をリフローさせて開口径を縮小させると言う
セルフアライメント手法により、イオン注入領域を微細
な面積、例えば０．１μm 単位で縮小できると評価でき
る。As described above, according to the method of the present invention, the self-alignment technique of reflowing the photoresist layer to reduce the opening diameter can reduce the ion implantation region in a fine area, for example, in a unit of 0.1 μm. Can be evaluated.
【００１９】以上の実施例では、ＣＣＤ撮像素子の垂直
転送部の形成を例にして説明したが、ＭＯＳトランジス
タの製造方法で広く用いられるＬＤＤ法と同様の作用に
よって、開口縁の両端において不純物濃度勾配が緩やか
になる。よって、ＭＯＳトランジスタの製造方法にも適
用できる。特に、ＬＤＤ型のＭＯＳＦＥＴの製造の際の
イオン注入に当たり、イオン注入領域の位置及び面積を
微細に調整する時にも適用できる。In the above-mentioned embodiments, the formation of the vertical transfer portion of the CCD image pickup device has been described as an example. However, by the same operation as the LDD method widely used in the manufacturing method of MOS transistors, the impurity concentration at both ends of the opening edge is increased. The slope becomes gentle. Therefore, it can be applied to a method of manufacturing a MOS transistor. In particular, it can be applied to finely adjust the position and area of the ion-implanted region in ion-implantation at the time of manufacturing an LDD type MOSFET.
【００２０】[0020]
【発明の効果】本発明によれば、半導体素子の製造にお
いて、基板上にホトレジスト層からなるマスクパターン
を形成し、ホトレジスト層をマスクにしてイオン注入す
る際、ホトレジスト層にリフロー熱処理を施して、マス
クパターンの開口部の下端縁の開口径を縮小させ、それ
によって（１）第１次イオン注入及び第２次イオン注入
を連続して行う場合でも、後に注入する第２次イオン注
入のイオン注入領域の面積を先に注入する第１次イオン
注入のイオン注入領域の面積よりも小さくでき、また
（２）パターンの開口面積変更を自己整合を保持しつつ
行える。本発明方法では、フォトリソグラフィステッパ
ーの合わせずれが含まれないため、精度の高いパターン
開口の位置、面積の微細調整を行うことができる。ま
た、本発明方法をＣＣＤ撮像素子の垂直転送部の形成に
適用した場合、スミア量及びノイズを低減させることが
できる。According to the present invention, in the manufacture of a semiconductor device, a mask pattern made of a photoresist layer is formed on a substrate, and when the photoresist layer is used as a mask for ion implantation, the photoresist layer is subjected to reflow heat treatment, The opening diameter of the lower edge of the opening of the mask pattern is reduced so that (1) even when the primary ion implantation and the secondary ion implantation are continuously performed, the ion implantation of the secondary ion implantation that is performed later is performed. The area of the region can be made smaller than the area of the ion-implanted region of the primary ion implantation that is first implanted, and (2) the opening area of the pattern can be changed while maintaining self-alignment. Since the method of the present invention does not include misalignment of the photolithography stepper, it is possible to perform fine adjustment of the position and area of the pattern opening with high accuracy. Further, when the method of the present invention is applied to the formation of the vertical transfer portion of the CCD image pickup device, the amount of smear and noise can be reduced.
【図１】本発明方法により製造したＣＣＤ素子有効画素
の積層構造を示すＨ方向断面図である。FIG. 1 is a sectional view in the H direction showing a laminated structure of effective pixels of a CCD element manufactured by the method of the present invention.
【図２】基板上にホトレジスト膜を成膜し、マスクパタ
ーンを形成し、第１次イオン注入を行って転送バリア部
を形成した状態での基板のＨ方向断面図である。FIG. 2 is a cross-sectional view of the substrate in the H direction in the state where a photoresist film is formed on the substrate, a mask pattern is formed, and primary ion implantation is performed to form a transfer barrier portion.
【図３】ホトレジスト層をリフローさせた状態での基板
のＨ方向断面図である。FIG. 3 is a cross-sectional view in the H direction of the substrate in a state where the photoresist layer has been reflowed.
【図４】第２次イオン注入を行って垂直転送部を形成し
た状態での基板のＨ方向断面図である。FIG. 4 is a cross-sectional view of the substrate in the H direction in the state where the vertical transfer portion is formed by performing the secondary ion implantation.
【図５】図４に引き続く工程で得た積層構造を示す基板
のＨ方向断面図である。5 is a cross-sectional view in the H direction of the substrate showing the laminated structure obtained in the process subsequent to FIG.
【図６】従来方法により製造したＣＣＤ素子有効画素の
積層構造を示すＨ方向断面図である。FIG. 6 is a cross-sectional view in the H direction showing a laminated structure of a CCD element effective pixel manufactured by a conventional method.
【図７】従来方法により形成した転送バリア部及び垂直
転送部を示す基板のＨ方向断面図である。FIG. 7 is a cross-sectional view in the H direction of a substrate showing a transfer barrier section and a vertical transfer section formed by a conventional method.
【図８】図７に引き続く工程で得た積層構造を示す基板
のＨ方向断面図である。8 is a cross-sectional view in the H direction of a substrate showing a laminated structure obtained in the process following the process of FIG.
１０ 従来方法により得たＣＣＤ撮像素子の有効画素の
積層構造 １１ Ｓｉ基板 １２ オーバーフローバリア １３ 絶縁膜 ２１ 転送バリア部 ２２ 垂直転送部 ２３ 読み出しバリア層 ２４ 受光部 ２５ ホール蓄積部 ２６ チャネルストップ ３１ 転送電極 ３２ 絶縁膜 ３３ ＰＳＧ膜 ３４ 遮光膜 ３５ 水平断面 ４０ ホトレジスト層 ４２ 開口部 ４４ 下端部 ４６ 端縁 ４８ 本発明方法により得たＣＣＤ撮像素子の有効画素
の積層構造10 Laminated Structure of Effective Pixels of CCD Image Sensor Obtained by Conventional Method 11 Si Substrate 12 Overflow Barrier 13 Insulating Film 21 Transfer Barrier Section 22 Vertical Transfer Section 23 Read Barrier Layer 24 Light Receiving Section 25 Hole Accumulating Section 26 Channel Stop 31 Transfer Electrode 32 Insulating film 33 PSG film 34 Light-shielding film 35 Horizontal section 40 Photoresist layer 42 Opening part 44 Lower end part 46 End edge 48 Laminated structure of effective pixels of CCD image pickup device obtained by the method of the present invention
Claims (2)
パターンを形成し、ホトレジスト層をマスクにしてイオ
ン注入する際、 ホトレジスト層にリフロー熱処理を施して、マスクパタ
ーンの開口部の下端縁の開口径を縮小させ、それによっ
てイオン注入領域の位置及び面積を調整することを特徴
とするイオン注入方法。1. A mask pattern made of a photoresist layer is formed on a substrate, and when ion implantation is performed using the photoresist layer as a mask, the photoresist layer is subjected to reflow heat treatment to reduce the opening diameter of the lower end edge of the opening of the mask pattern. An ion implantation method comprising reducing the size and adjusting the position and area of the ion implantation region.
で、基板の絶縁膜上にホトレジスト層からなるマスクパ
ターンを形成し、ホトレジスト層をマスクにしてイオン
注入により転送バリア部を形成し、次いで別のイオンを
注入して垂直転送部を形成するに当たり、 ホトレジスト層にリフロー熱処理を施して、マスクパタ
ーンの開口部の下端縁の開口径を縮小させ、それによっ
て垂直転送部を形成するイオン注入領域の位置及び面積
を調整することを特徴とするイオン注入方法。2. A step of forming a vertical transfer portion of a CCD image pickup device, wherein a mask pattern made of a photoresist layer is formed on an insulating film of a substrate, a transfer barrier portion is formed by ion implantation using the photoresist layer as a mask, and then, In forming another vertical transfer part by implanting another ion, the photoresist layer is subjected to a reflow heat treatment to reduce the opening diameter of the lower end edge of the opening of the mask pattern, thereby forming the vertical transfer part. An ion implantation method, characterized in that the position and area of the ion are adjusted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34677195A JP3867312B2 (en) | 1995-12-13 | 1995-12-13 | Ion implantation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34677195A JP3867312B2 (en) | 1995-12-13 | 1995-12-13 | Ion implantation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09162137A true JPH09162137A (en) | 1997-06-20 |
| JP3867312B2 JP3867312B2 (en) | 2007-01-10 |
Family
ID=18385714
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34677195A Expired - Fee Related JP3867312B2 (en) | 1995-12-13 | 1995-12-13 | Ion implantation method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3867312B2 (en) |
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|---|---|
| JP3867312B2 (en) | 2007-01-10 |
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