JP2730262B2 - Method for manufacturing semiconductor device - Google Patents
Method for manufacturing semiconductor deviceInfo
- Publication number
- JP2730262B2 JP2730262B2 JP2117189A JP11718990A JP2730262B2 JP 2730262 B2 JP2730262 B2 JP 2730262B2 JP 2117189 A JP2117189 A JP 2117189A JP 11718990 A JP11718990 A JP 11718990A JP 2730262 B2 JP2730262 B2 JP 2730262B2
- Authority
- JP
- Japan
- Prior art keywords
- boron
- semiconductor substrate
- glass layer
- semiconductor device
- wafer
- 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
Landscapes
- Formation Of Insulating Films (AREA)
- Recrystallisation Techniques (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、半導体基板表面に硼素ガラス層を形成した
のち熱処理により硼素を基体内部へ拡散させる工程を含
む半導体素子の製造方法に関する。Description: BACKGROUND OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, comprising a step of forming a boron glass layer on a semiconductor substrate surface and then diffusing boron into the inside of a base by heat treatment.
〔従来の技術〕 半導体素子の製造のためのウエーハプロセスにおい
て、深さ40μm以上のp型拡散領域を形成する場合、不
純物濃度を高くしかつライフタイムの低下を防止する拡
散法を再現性良く実施するには、BNの焼結体であり、PB
Nと略されるパイロリテックBN(焦性BN)を拡散源とし
て用いるのが最良とされている。拡散工程は、ドープと
ドライブとに大別できる。ドープ時にはPBN板よりB2O3
がウエーハに向かって飛び、ウエーハ面の酸化膜マスク
に覆われない領域からウエーハ内に硼素が拡散されると
同時にウエーハ面上に高硼素濃度の硼素ガラス層ができ
る。ドライブ時には、表面に硼素ガラス層を有するウエ
ーハをそのまま熱処理して所定の深さまで硼素を拡散さ
せる。水洗あるいは薬液処理などを行ってウエーハ上の
硼素ガラス層を除去すると、高濃度で深いp型領域を得
ることができないので、そのまま拡散を行う。[Prior art] In a wafer process for manufacturing a semiconductor device, when a p-type diffusion region having a depth of 40 μm or more is formed, a diffusion method for increasing the impurity concentration and preventing a decrease in lifetime is performed with good reproducibility. To be a sintered body of BN, PB
It is best to use Pyrolytec BN (pyrolytic BN), abbreviated as N, as the diffusion source. The diffusion process can be roughly divided into dope and drive. B 2 O 3 from the PBN plate during doping
Flies toward the wafer, boron is diffused into the wafer from a region of the wafer surface that is not covered by the oxide film mask, and at the same time, a boron glass layer having a high boron concentration is formed on the wafer surface. At the time of driving, a wafer having a boron glass layer on its surface is directly heat-treated to diffuse boron to a predetermined depth. If the boron glass layer on the wafer is removed by washing with water or chemical treatment, a high concentration and deep p-type region cannot be obtained.
上記のような方法で硼素の拡散を行うと、ドライブ工
程前にウエーハ面上に粒径20〜100μm程度の結晶状の
硼素粒が発生しているのが見られる。この粒が存在する
と、ドライブ工程では硼素がフォトリソグラフィでパタ
ーニングされた酸化膜でマスクされた部分を突き抜け、
必要でない部分にp型領域をつくる。これにより、n型
領域の抵抗値が異常となる。また、粒がマスクの細かい
パターンの上に発生すると、ドライブ工程で生ずる両側
のp型領域を電気的に短絡してしまう。このように大き
い結晶状の硼素粒の発生は製造工程における半導体素子
の良品率の低下の原因となる。このドープ後に発生する
結晶状の硼素粒は、水洗により簡単に除去できる。しか
し、それと同時に前述のように高濃度硼素ガラス層も除
去されてしまうため、水洗いを行うことができない。When boron is diffused by the above-described method, it is observed that crystalline boron grains having a grain size of about 20 to 100 μm are generated on the wafer surface before the driving step. When these grains are present, boron penetrates through the portion masked by the oxide film patterned by photolithography in the drive process,
Create p-type regions where not needed. As a result, the resistance value of the n-type region becomes abnormal. Further, when the grains are generated on the fine pattern of the mask, the p-type regions on both sides generated in the driving step are electrically short-circuited. The generation of such large crystalline boron particles causes a reduction in the yield of semiconductor elements in the manufacturing process. The crystalline boron particles generated after the doping can be easily removed by washing with water. However, at the same time, the high-concentration boron glass layer is also removed as described above, so that water washing cannot be performed.
本発明の目的は、上記の問題の解決のための根本的な
対策として大きい結晶状の硼素粒の発生を阻止してドー
プを行う半導体素子の製造方法を提供することにある。An object of the present invention is to provide a method of manufacturing a semiconductor device in which doping is performed by preventing generation of large crystalline boron grains as a fundamental measure for solving the above-mentioned problem.
上記の目的を達成するために、本発明は、半導体基板
を酸化硼素を含む雰囲気中で加熱して半導体基板表面に
硼素ガラス層を付着させるドープ工程と、硼素ガラス層
の付着した半導体基板を加熱して基板内に硼素を40μm
以上の深さに拡散させるドライブ工程とを含む半導体素
子の製造方法において、ドープ工程の後半導体基板を窒
素雰囲気中で1.5時間以上放置し、次いでドライブ工程
に移るものとする。In order to achieve the above object, the present invention provides a doping step of heating a semiconductor substrate in an atmosphere containing boron oxide to deposit a boron glass layer on the surface of the semiconductor substrate, and heating the semiconductor substrate having the boron glass layer deposited thereon. 40μm boron in the substrate
In the method of manufacturing a semiconductor device including the driving step of diffusing to the above depth, the semiconductor substrate is left in a nitrogen atmosphere for 1.5 hours or more after the doping step, and then the driving step is started.
硼素ガラスが水分を含む雰囲気に接触すると、B2O3+
H2O→2HBO2の反応が起こることが知られており、水が多
いと水溶液になるが、近傍に硼素結晶がある場合にはそ
の結晶に付着して再結晶し、大きな結晶粒が発生すると
考えられる。実際に観察した結果では、大結晶化した硼
素粒の近傍には小さい硼素粒は見られなかった。そして
ドープ工程後、窒素雰囲気中に1.5時間放置すると、水
との反応による大結晶化が防止され、大きな結晶粒の発
生は100%抑えることができることが確認された。When boron glass comes into contact with an atmosphere containing moisture, B 2 O 3 +
It is known that the reaction of H 2 O → 2HBO 2 occurs.When there is much water, it becomes an aqueous solution, but if there is a boron crystal nearby, it adheres to the crystal and recrystallizes, generating large crystal grains. It is thought that. As a result of actual observation, no small boron grains were found near the large crystallized boron grains. After the doping step, when left in a nitrogen atmosphere for 1.5 hours, it was confirmed that large crystallization due to reaction with water was prevented, and the generation of large crystal grains could be suppressed by 100%.
第1図(a)〜(c)は本発明の一実施例におけるp
型領域形成工程を概念的に示す。先ず、n型シリコンウ
エーハ1の表面上に全面的に酸化膜2を形成した後、フ
ォトリソグラフィでパターニングして開口部3を開けた
(図(a))。次に、この複数枚のウエーハを石英ボー
トの溝に立て、PBN板と共にN2などのキャリアガス中で
約750℃に加熱してドープ工程を行い、表面に高濃度の
硼素ガラス層4を付着させた(図(b))。つづいて、
ウエーハをボートと共に10/分の流量でN2ガスを流し
た雰囲気中に放置して1.5時間以上保管する。この時の
放置条件は、N2ガス量と放置時間だけである。このあ
と、湿度30%以下のクリーンブースの下でウエーハをボ
ートからはずし、別のボートの溝に立てる。このボート
をN2などのキャリアガスを流す拡散炉に移し、1000℃以
上でのドライブ工程を行って所定の深さのp型領域5を
形成した(図(c))。このような工程でp型領域を形
成したときには、付着硼素粒からの拡散による望ましく
ない位置でのp型領域の形成は認められなかった。FIGS. 1 (a) to 1 (c) show p in one embodiment of the present invention.
4 schematically illustrates a mold region forming step. First, an oxide film 2 was entirely formed on the surface of an n-type silicon wafer 1, and then patterned by photolithography to open an opening 3 (FIG. 1A). Next, the plurality of wafers are set in a groove of a quartz boat, and heated together with a PBN plate at about 750 ° C. in a carrier gas such as N 2 to perform a doping process, and a high-concentration boron glass layer 4 is deposited on the surface. (Figure (b)). Then,
The wafer is stored together with the boat in an atmosphere of N 2 gas at a flow rate of 10 / min for at least 1.5 hours. The leaving conditions at this time are only the N 2 gas amount and the leaving time. Thereafter, the wafer is removed from the boat under a clean booth with a humidity of 30% or less, and is set up in a groove on another boat. This boat was transferred to a diffusion furnace through which a carrier gas such as N 2 flows, and a drive process was performed at 1000 ° C. or higher to form a p-type region 5 having a predetermined depth (FIG. (C)). When the p-type region was formed in such a process, formation of the p-type region at an undesired position due to diffusion from the attached boron grains was not recognized.
本発明によれば、ドープ工程で形成した硼素ガラス層
からの大きな結晶状の硼素粒の発生を、ドープ工程後半
導体基板を窒素雰囲気中に放置することにより抑制し、
マスクを通り抜ける拡散によって生ずる望ましくない硼
素拡散領域の形成を防止することができた。これによ
り、硼素拡散工程での不良品の発生を大幅に低減するこ
とができ、良品率を高いレベルで維持することが可能に
なった。According to the present invention, generation of large crystalline boron grains from the boron glass layer formed in the doping step is suppressed by leaving the semiconductor substrate in a nitrogen atmosphere after the doping step,
The formation of undesirable boron diffusion regions caused by diffusion through the mask could be prevented. As a result, the generation of defective products in the boron diffusion step can be greatly reduced, and the non-defective product ratio can be maintained at a high level.
第1図は本発明の一実施例の硼素拡散工程を(a)ない
し(c)の順に概念的に示す断面図である。 1:シリコンウエーハ、2:酸化膜、4:硼素ガラス層、5:p
型領域。FIG. 1 is a sectional view conceptually showing a boron diffusion step of one embodiment of the present invention in the order of (a) to (c). 1: silicon wafer, 2: oxide film, 4: boron glass layer, 5: p
Type area.
Claims (1)
熱して半導体基板表面に硼素ガラス層を付着させるドー
プ工程と、硼素ガラス層の付着した半導体基板を加熱し
て基板内に硼素を40μm以上の深さに拡散させるドライ
ブ工程とを含む半導体素子の製造方法において、ドープ
工程の後半導体基板を窒素雰囲気中で1.5時間以上放置
し、次いでドライブ工程に移ることを特徴とする半導体
素子の製造方法。1. A doping step of heating a semiconductor substrate in an atmosphere containing boron oxide to deposit a boron glass layer on the surface of the semiconductor substrate, and heating the semiconductor substrate on which the boron glass layer is deposited to deposit boron in the substrate by 40 μm. A method of manufacturing a semiconductor device, comprising: a driving step of diffusing the semiconductor substrate to the above depth; and after the doping step, leaving the semiconductor substrate in a nitrogen atmosphere for 1.5 hours or more, and then moving to a driving step. Method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2117189A JP2730262B2 (en) | 1990-05-07 | 1990-05-07 | Method for manufacturing semiconductor device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2117189A JP2730262B2 (en) | 1990-05-07 | 1990-05-07 | Method for manufacturing semiconductor device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0414218A JPH0414218A (en) | 1992-01-20 |
JP2730262B2 true JP2730262B2 (en) | 1998-03-25 |
Family
ID=14705610
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2117189A Expired - Fee Related JP2730262B2 (en) | 1990-05-07 | 1990-05-07 | Method for manufacturing semiconductor device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2730262B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009057088A (en) * | 2007-08-31 | 2009-03-19 | Yada Seisakusho:Kk | Standing posture retaining apparatus for tray packing with chinese meat dumpling |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4847769A (en) * | 1971-10-18 | 1973-07-06 |
-
1990
- 1990-05-07 JP JP2117189A patent/JP2730262B2/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4847769A (en) * | 1971-10-18 | 1973-07-06 |
Also Published As
Publication number | Publication date |
---|---|
JPH0414218A (en) | 1992-01-20 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
LAPS | Cancellation because of no payment of annual fees |