JPH0660402B2 - Selective growth method for tungsten film - Google Patents
Selective growth method for tungsten filmInfo
- Publication number
- JPH0660402B2 JPH0660402B2 JP17143685A JP17143685A JPH0660402B2 JP H0660402 B2 JPH0660402 B2 JP H0660402B2 JP 17143685 A JP17143685 A JP 17143685A JP 17143685 A JP17143685 A JP 17143685A JP H0660402 B2 JPH0660402 B2 JP H0660402B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- tungsten film
- gas
- selective growth
- tungsten
- 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
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- Chemical Vapour Deposition (AREA)
- Electrodes Of Semiconductors (AREA)
Description
【発明の詳細な説明】 [概要] 六弗化タングステンと水素との反応ガスを熱分解して、
タングステン膜を選択成長し、次に、反応ガスの流入を
止め、真空吸引によつて生成ガスを除去する。このよう
な操作を繰り返えして、所要の膜厚のタングステン膜を
選択成長する。DETAILED DESCRIPTION OF THE INVENTION [Outline] The reaction gas of tungsten hexafluoride and hydrogen is thermally decomposed,
The tungsten film is selectively grown, then the inflow of the reaction gas is stopped, and the generated gas is removed by vacuum suction. By repeating such an operation, a tungsten film having a required film thickness is selectively grown.
[産業上の利用分野] 本発明は半導体装置の製造に用いるタングステン膜の選
択成長方法に関する。[Field of Industrial Application] The present invention relates to a selective growth method of a tungsten film used for manufacturing a semiconductor device.
ICなどの半導体装置においては、半導体基板上に半導
体素子やその他の回路素子が形成され、それらの領域か
ら導出する電極配線が上面に多数設けられる。In a semiconductor device such as an IC, a semiconductor element and other circuit elements are formed on a semiconductor substrate, and a large number of electrode wirings leading from these regions are provided on the upper surface.
それらの電極配線は、従前より現在までアルミニウム膜
またはその合金膜が用いられているが、アルミニウムは
融点が低いのが欠点で、多層配線を形成する場合に、層
間絶縁膜の形成に制約を与える欠点がある。そのため、
それに代わる配線材料として、導電性多結晶シリコン膜
が汎用されているが、これは導電性が余り良くない問題
があり、最近では、電気伝導度の良い高融点金属膜ある
いはそのシリサイド膜を電極配線に使用する方法が採ら
れている。Aluminum electrodes or their alloy films have been used for these electrode wirings up to now, but aluminum has a drawback that its melting point is low, which limits the formation of interlayer insulating films when forming multilayer wirings. There are drawbacks. for that reason,
A conductive polycrystalline silicon film is widely used as an alternative wiring material, but this has a problem that the conductivity is not so good, and recently, a refractory metal film having good electrical conductivity or a silicide film thereof has been used as an electrode wiring. The method used for is adopted.
ところが、このような高融点金属膜の被着方法を種々検
討している過程で、タングステン膜はフオトプロセスを
適用しなくても、半導体基板へ選択的に成長することが
判つてきた。しかし、その選択成長法は未だ十分なもの
ではなく、十分満足な選択成長法の確立が要望されてい
る。However, in the course of studying various methods of depositing such a refractory metal film, it has been found that the tungsten film selectively grows on the semiconductor substrate without applying the photo process. However, the selective growth method is not yet sufficient, and establishment of a sufficiently satisfactory selective growth method is desired.
[従来の技術と発明が解決しようとする問題点] このようなタングステン膜の選択成長法は、勿論、化学
気相成長(CVD)法による成長方法であるが、それは
六弗化タングステン(WF6)と水素(H2)とを混合
した反応ガスを熱分解させて被着させるもので、その反
応式は次式のようになつている。[Problems to be Solved by the Related Art and Invention] The selective growth method of the tungsten film is, of course, a growth method by chemical vapor deposition (CVD) method, which is tungsten hexafluoride (WF 6). ) And hydrogen (H 2 ) are mixed and the reaction gas is thermally decomposed and deposited. The reaction formula is as follows.
WF6+3H2→W+6HF この反応式から判るように、弗酸(HF)ガスが生成さ
れるため、そのHFガスが二酸化シリコン(SiO2)膜
面をエッチングして、そのため、タングステン膜がシリ
コン基板上にのみ成長し、SiO2膜の上に成長しない選
択成長がおこなわれると考えられている。WF 6 + 3H 2 → W + 6HF As can be seen from this reaction formula, since hydrofluoric acid (HF) gas is generated, the HF gas etches the silicon dioxide (SiO 2 ) film surface, so that the tungsten film is removed from the silicon substrate It is considered that selective growth is performed only on the SiO 2 film and not on the SiO 2 film.
しかし、選択成長膜厚が3000Å程度以上になると、もは
や選択性がなくなつて、SiO2膜の上にもタングステン
膜が被着するようになる。例えば、第3図に示す断面図
のように、シリコン基板1上に設けた膜厚1μmのSiO
2膜2に電極窓3を形成して、その電極窓にタングステ
ン膜4を被着させると、選択成長だけで電極窓3を埋没
させることはできない。従つて、現在、タングステン膜
は5000Å程度、あるいはそれ以下を選択成長させている
に過ぎない。However, when the selectively grown film thickness is about 3000 Å or more, the selectivity is lost, and the tungsten film is deposited on the SiO 2 film. For example, as shown in the sectional view of FIG. 3, a 1 μm-thick SiO 2 film provided on the silicon substrate 1
2 When the electrode window 3 is formed in the film 2 and the tungsten film 4 is deposited on the electrode window, the electrode window 3 cannot be buried only by selective growth. Therefore, at present, the tungsten film is only selectively grown to a thickness of about 5000Å or less.
この例で、電極窓を導電体膜で埋没させることは、配線
層を平坦化させるために重要なことで、上記のように被
着量が少ないと、電極窓は更に他の導電体膜で埋没させ
なければならない。In this example, burying the electrode window with a conductor film is important for flattening the wiring layer, and if the deposition amount is small as described above, the electrode window will be covered with another conductor film. Must be buried.
本発明は、上記のような成長膜厚に限界のあるタングス
テン膜の選択成長を解消させて、所要膜厚のタングステ
ン膜を選択成長させる成長法を提案するものである。The present invention proposes a growth method for eliminating the above-mentioned selective growth of a tungsten film having a limited growth film thickness and selectively growing a tungsten film of a required film thickness.
[問題点を解決するための手段] その目的は、六弗化タングステンと水素からなる反応ガ
スを熱分解して、半導体基板上に選択的にタングステン
膜を成長する成長工程において、上記反応ガスの導入を
間欠的に中止し、反応室の真空度を高くする操作を加え
るようにしたタングステン膜の選択成長法によって達成
される。[Means for Solving the Problems] The purpose thereof is to perform thermal decomposition of a reaction gas composed of tungsten hexafluoride and hydrogen to selectively grow a tungsten film on a semiconductor substrate. This is achieved by a selective growth method of a tungsten film in which the introduction is intermittently stopped and an operation of increasing the vacuum degree of the reaction chamber is added.
[作用] 即ち、本発明は、発生したHFによつて下地が荒らされ
ないように、選択成長の工程途中で反応ガスの導入を止
め、過剰に生成されたHFを真空吸引して一旦除去す
る。このようにして、間欠的に選択成長すると、膜厚に
限界なくタングステン膜を選択成長することができる。[Operation] That is, according to the present invention, the introduction of the reaction gas is stopped during the process of the selective growth and the excessively generated HF is temporarily sucked and removed so that the underlayer is not roughened by the generated HF. . In this way, if the selective growth is performed intermittently, the tungsten film can be selectively grown with no limit on the film thickness.
[実施例] 以下、図面を参照して実施例によつて詳細に説明する。[Examples] Hereinafter, examples will be described in detail with reference to the drawings.
第1図は本発明を適用するCVD装置の概要図を示して
おり、11はシリコン基板,12は反応室,13は加熱体,14
は真空排気口,15はWF6ガス流入口,16はH2ガス流
入口である。FIG. 1 shows a schematic view of a CVD apparatus to which the present invention is applied. 11 is a silicon substrate, 12 is a reaction chamber, 13 is a heating body, 14
Is a vacuum exhaust port, 15 is a WF 6 gas inlet, and 16 is an H 2 gas inlet.
このようなCVD装置の反応室2を 300〜325 ℃の間の
一定温度に加熱しておいて、ガス流入口15, 16よりWF
6ガスとH2ガスとを流入させ、他端より真空吸引して
反応室12の内部を0.3Torr程度の減圧度に保つてお
く。ガス流入量は、例えば、WF6ガス量が30cc/分に
対して、H2ガス量を 400cc/分程度にする。又、この
時、WF6ガスは窒素(N2)ガスで希釈して、流入さ
せる方法も採られる。The reaction chamber 2 of such a CVD apparatus is heated to a constant temperature of 300 to 325 ° C., and WF is supplied from the gas inlets 15 and 16.
6 gas and H 2 gas are caused to flow in, and vacuum suction is performed from the other end to keep the inside of the reaction chamber 12 at a reduced pressure degree of about 0.3 Torr. The gas inflow amount is, for example, about 400 cc / min for H 2 gas while 30 cc / min for WF 6 gas. Further, at this time, a method of diluting the WF 6 gas with nitrogen (N 2 ) gas and allowing the WF 6 gas to flow in may be adopted.
そうすると、反応室の中でWF6ガスが熱分解して、タ
ングステン膜が成長する。その時、第3図に示す断面図
のように、SiO2膜2の上にはタングステン膜は被着せ
ず、電極窓3のシリコン基板1の上にのみタングステン
膜4が被着する。Then, the WF 6 gas is thermally decomposed in the reaction chamber, and the tungsten film grows. At that time, as shown in the sectional view of FIG. 3, the tungsten film is not deposited on the SiO 2 film 2, but the tungsten film 4 is deposited only on the silicon substrate 1 of the electrode window 3.
このようにして、30分間反応させて、1000Å程度の膜厚
を成長した後、WF6ガスとH2ガスとの流入を中止す
る。しかし、真空吸引は続行されるから、減圧度は高く
なり、反応室2は0.1Torr程度の真空度になる。そう
すると、再びWF6ガスとH2ガスとを流入させ、同様
に30分間反応させて、更に1000Å程度の膜厚のタングス
テン膜を成長する。In this way, after reacting for 30 minutes to grow a film thickness of about 1000 Å, the inflow of WF 6 gas and H 2 gas is stopped. However, since the vacuum suction is continued, the degree of reduced pressure becomes high, and the degree of vacuum in the reaction chamber 2 becomes about 0.1 Torr. Then, the WF 6 gas and the H 2 gas are caused to flow in again, and they are similarly reacted for 30 minutes to further grow a tungsten film having a film thickness of about 1000 Å.
かくして、このような操作を繰り換えして、選択成長す
ると、第2図に示す断面図のように、電極窓3をタング
ステン膜4で埋没させることができる。このようにすれ
ば、選択成長の膜厚が制限されるなくなるのは、過度に
生成されたHFが真空吸引して除去され、SiO2膜面が
過剰のHFによつて荒らされずに済むからと考えられ
る。Thus, by repeating such an operation and performing selective growth, the electrode window 3 can be buried with the tungsten film 4 as shown in the sectional view of FIG. In this way, the thickness of the selective growth is no longer limited because excessively generated HF is removed by vacuum suction and the SiO 2 film surface is not roughened by excessive HF. Conceivable.
上記例では、電極窓を埋没させて、配線層を平坦化する
工程について説明したが、このように、所要の膜厚を選
択成長できることは、その他の製造工程にも、種々の好
影響を与えることは云うまでもないことである。In the above example, the step of burying the electrode window and flattening the wiring layer has been described. However, the ability to selectively grow the required film thickness has various favorable effects on other manufacturing steps as well. Needless to say.
[発明の効果] 以上の説明から明らかなように、本発明によれば所要膜
厚のタングステン膜が選択成長できて、ICの高性能・
高品質化や高密度化に大きく貢献するものである。[Effects of the Invention] As is clear from the above description, according to the present invention, a tungsten film having a required film thickness can be selectively grown, and high performance of IC
This greatly contributes to higher quality and higher density.
第1図は本発明を適用するCVD装置の概要図、 第2図は本発明にかかるタングステン膜を選択成長した
電極窓の断面図、 第3図は従来のタングステン膜を選択成長した電極窓の
断面図である。 図において、 1,11はシリコン基板、2はSiO2膜、 3は電極窓、4はタングステン膜、 12は反応炉、13は加熱体、 14は真空排気口、15はWF6ガス流入口、 16はH2ガス流入口 を示している。FIG. 1 is a schematic view of a CVD apparatus to which the present invention is applied, FIG. 2 is a sectional view of an electrode window in which a tungsten film according to the present invention is selectively grown, and FIG. 3 is a conventional electrode window in which a tungsten film is selectively grown. FIG. In the figure, 1 and 11 are a silicon substrate, 2 is a SiO 2 film, 3 is an electrode window, 4 is a tungsten film, 12 is a reaction furnace, 13 is a heating body, 14 is a vacuum exhaust port, 15 is a WF 6 gas inlet port, Reference numeral 16 indicates an H 2 gas inlet.
Claims (1)
スを熱分解して、半導体基板上に選択的にタングステン
膜を成長する成長工程において、上記反応ガスの流入を
間欠的に中止し、反応室の真空度を高くする操作を加え
るようにしたことを特徴とするタングステン膜の選択成
長方法。1. In a growth step of thermally decomposing a reaction gas composed of tungsten hexafluoride and hydrogen to selectively grow a tungsten film on a semiconductor substrate, an inflow of the reaction gas is intermittently stopped to carry out a reaction. A method for selectively growing a tungsten film, characterized in that an operation for increasing the degree of vacuum in a chamber is added.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP17143685A JPH0660402B2 (en) | 1985-08-02 | 1985-08-02 | Selective growth method for tungsten film |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP17143685A JPH0660402B2 (en) | 1985-08-02 | 1985-08-02 | Selective growth method for tungsten film |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6233768A JPS6233768A (en) | 1987-02-13 |
JPH0660402B2 true JPH0660402B2 (en) | 1994-08-10 |
Family
ID=15923085
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP17143685A Expired - Lifetime JPH0660402B2 (en) | 1985-08-02 | 1985-08-02 | Selective growth method for tungsten film |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0660402B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003064724A1 (en) * | 2001-12-17 | 2003-08-07 | Applied Materials, Inc. | Process for tungsten deposition by pulsed gas flow cvd |
-
1985
- 1985-08-02 JP JP17143685A patent/JPH0660402B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPS6233768A (en) | 1987-02-13 |
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