JP2000235963A - Manufacture of barrier film and the barrier film - Google Patents
Manufacture of barrier film and the barrier filmInfo
- Publication number
- JP2000235963A JP2000235963A JP11038041A JP3804199A JP2000235963A JP 2000235963 A JP2000235963 A JP 2000235963A JP 11038041 A JP11038041 A JP 11038041A JP 3804199 A JP3804199 A JP 3804199A JP 2000235963 A JP2000235963 A JP 2000235963A
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- Prior art keywords
- thin film
- gas
- reducing gas
- barrier film
- flow rate
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- Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は半導体デバイス用の
銅配線の技術分野にかかり、特に、銅配線膜と絶縁膜の
間に設けられるバリア膜の製造方法に関する。The present invention relates to the technical field of copper wiring for semiconductor devices, and more particularly, to a method of manufacturing a barrier film provided between a copper wiring film and an insulating film.
【０００２】[0002]
【従来の技術】近年では、半導体デバイスには増々高速
動作が要求されており、そのため、アルミニウム配線に
換え、低抵抗の銅配線が研究されている。2. Description of the Related Art In recent years, semiconductor devices are increasingly required to operate at higher speeds. Therefore, research has been conducted on low-resistance copper wiring instead of aluminum wiring.
【０００３】しかし、銅は半導体結晶中では不純物であ
り、しかもシリコン結晶中やシリコン酸化物中での拡散
係数が大きいという問題がある。そのため、窒化タング
ステン薄膜等の高融点金属の窒化物薄膜をバリア膜に用
い、シリコン基板やシリコン酸化物薄膜表面にバリア膜
を形成した後、その表面に銅配線膜を形成している。However, there is a problem that copper is an impurity in a semiconductor crystal and has a large diffusion coefficient in a silicon crystal or a silicon oxide. Therefore, a nitride thin film of a refractory metal such as a tungsten nitride thin film is used as a barrier film, a barrier film is formed on the surface of a silicon substrate or a silicon oxide thin film, and then a copper wiring film is formed on the surface.
【０００４】バリア膜を形成するためには、スパッタリ
ング法や熱ＣＶＤ法が用いられており、スパッタリング
法の場合は高融点金属をターゲットにし、熱ＣＶＤ法の
場合は、下記のような還元反応によって窒化物薄膜を形
成している。(１)式はタングステンの場合、(２)式はチ
タンの場合である。 ４ＷＦ6＋８ＮＨ3 → ２Ｗ2Ｎ＋２４ＨＦ＋３Ｎ2 …(１) ＴｉＣｌ4＋ＮＨ3 → ＴｉＮ＋２ＨＣｌ＋１／２Ｈ2 …(２)In order to form a barrier film, a sputtering method or a thermal CVD method is used. In the case of the sputtering method, a high melting point metal is used as a target, and in the case of the thermal CVD method, a reduction reaction as described below is performed. A nitride thin film is formed. Equation (1) is for tungsten, and equation (2) is for titanium. 4WF 6 + 8NH 3 → 2W 2 N + 24HF + 3N 2 (1) TiCl 4 + NH 3 → TiN + 2HCl + 1 / 2H 2 (2)
【０００５】多層配線の半導体デバイスを形成する場
合、層間絶縁膜を挟んで銅配線を積層させる必要がある
が、高速動作を要求される半導体デバイスでは、信号の
伝達遅延を少なくするため、銅配線の抵抗値の他、層間
絶縁膜の容量値やバリア膜の抵抗値を小さくする必要が
ある。具体的にはバリア膜には、２００〜３００μΩｃ
ｍの低抵抗が求められている。In the case of forming a semiconductor device having a multi-layer wiring, it is necessary to stack copper wiring with an interlayer insulating film interposed therebetween. However, in a semiconductor device requiring high-speed operation, a copper wiring is required to reduce signal transmission delay. , It is necessary to reduce the capacitance value of the interlayer insulating film and the resistance value of the barrier film. Specifically, the barrier film has a thickness of 200 to 300 μΩc.
m is required.
【０００６】スパッタリング法では、低抵抗の窒化物薄
膜を形成できるが、ステップカバレッジが悪く、高アス
ペクト比のヴィアホール内にバリア膜を均一に形成する
ことができない。In the sputtering method, a nitride thin film having a low resistance can be formed, but the step coverage is poor, and a barrier film cannot be formed uniformly in a via hole having a high aspect ratio.
【０００７】他方、熱ＣＶＤ法の場合、ヴィアホール内
に均一なバリア膜を形成することができるが、低誘電率
の層間絶縁膜は５００℃以上の高温に曝されると誘電率
が高くなってしまうため、熱ＣＶＤ法での成膜温度は４
００℃〜５００℃が上限となっており、その成膜温度で
は、例えばタングステン窒化物の薄膜の場合は、比抵抗
が数千μΩｃｍにもなってしまい、低抵抗のバリア膜が
得られない。On the other hand, in the case of the thermal CVD method, a uniform barrier film can be formed in a via hole, but the dielectric constant of an interlayer insulating film having a low dielectric constant increases when exposed to a high temperature of 500 ° C. or more. Therefore, the film formation temperature in the thermal CVD method is 4
The upper limit is from 00 ° C. to 500 ° C., and at the film formation temperature, for example, in the case of a tungsten nitride thin film, the specific resistance is as high as several thousand μΩcm, and a low-resistance barrier film cannot be obtained.
【０００８】ＣＶＤ法でも、有機金属を使用したＭＯＣ
ＶＤ方法や、プラズマＣＶＤ方法によれば、低温で低抵
抗のバリア膜を形成できるが、有機金属は高価であり、
他方、プラズマＣＶＤ方法はステップカバレッジが悪い
という問題があり、採用には至っていない。[0008] Even in the CVD method, an MOC using an organic metal is used.
According to the VD method or the plasma CVD method, a low-resistance barrier film can be formed at a low temperature, but an organic metal is expensive.
On the other hand, the plasma CVD method has a problem of poor step coverage, and has not been adopted yet.
【０００９】[0009]
【発明が解決しようとする課題】本発明は上記従来技術
の不都合を解決するために創作されたものであり、その
目的は、低比抵抗でステップカバレッジが良好なバリア
膜を提供することにある。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art, and an object of the present invention is to provide a barrier film having a low specific resistance and a good step coverage. .
【００１０】[0010]
【課題を解決するための手段】本発明の発明者等は、従
来の熱ＣＶＤ方法で形成した高融点金属の窒化物薄膜を
分析したところ、高融点金属原子が不足した状態になっ
ていることを見出した。例えばタングステンの場合、従
来技術のタングステン窒化物では化学量論的な組成(Ｗ2
Ｎ)になっておらず、ＷｘＮ(ｘは１．５乃至１．６程
度)になっている。このような窒化物中の金属原子の不
足が窒化物薄膜の結晶性を悪化させ、抵抗値を高くして
いる原因と考えられる。The inventors of the present invention have analyzed the refractory metal nitride thin film formed by the conventional thermal CVD method and found that the refractory metal atoms are in short supply. Was found. For example, in the case of tungsten, a stoichiometric composition (W 2
N) and WxN (x is about 1.5 to 1.6). It is considered that such a shortage of metal atoms in the nitride deteriorates the crystallinity of the nitride thin film and increases the resistance value.
【００１１】本発明は上記知見に基づいて創作されたも
のであり、高融点金属の窒化物の組成を化学量論的な値
に近づけるために、請求項１記載の発明は、化学構造中
に高融点金属を有する原料ガスと、窒素原子を有する含
窒素還元ガスとを真空雰囲気中に導入し前記真空雰囲気
中に置かれた基板上に前記高融点金属の窒化物薄膜を形
成するバリア膜製造方法であって、前記真空雰囲気中
に、窒素原子を有さない補助還元ガスを導入することを
特徴とする。The present invention has been made on the basis of the above findings. In order to make the composition of the nitride of the high melting point metal close to the stoichiometric value, the invention according to claim 1 includes a chemical structure Production of a barrier film for introducing a source gas having a high melting point metal and a nitrogen-containing reducing gas having a nitrogen atom into a vacuum atmosphere to form a nitride thin film of the high melting point metal on a substrate placed in the vacuum atmosphere The method is characterized in that an auxiliary reducing gas having no nitrogen atom is introduced into the vacuum atmosphere.
【００１２】請求項２記載の発明は、請求項１記載のバ
リア膜製造方法であって、前記含窒素還元ガスを、前記
原料ガスの流量に対して１倍以上の流量で導入し、前記
補助還元ガスを、前記含窒素還元ガスの流量に対して１
倍以上１０倍以下の流量で導入することを特徴とする。According to a second aspect of the present invention, there is provided the barrier film manufacturing method according to the first aspect, wherein the nitrogen-containing reducing gas is introduced at a flow rate one or more times higher than the flow rate of the raw material gas. The reducing gas is 1 to the flow rate of the nitrogen-containing reducing gas.
It is characterized by being introduced at a flow rate not less than twice and not more than 10 times.
【００１３】請求項３記載の発明は、請求項１記載のバ
リア膜製造方法であって、前記含窒素還元ガスを、前記
原料ガスの流量に対して１倍以上５倍以下の流量で導入
し、前記補助還元ガスを、前記含窒素還元ガスの流量に
対して２倍以上１０倍以下の流量で導入することを特徴
とする。According to a third aspect of the present invention, in the method of manufacturing a barrier film according to the first aspect, the nitrogen-containing reducing gas is introduced at a flow rate of 1 to 5 times the flow rate of the raw material gas. The auxiliary reducing gas is introduced at a flow rate of 2 to 10 times the flow rate of the nitrogen-containing reducing gas.
【００１４】請求項４記載の発明は、請求項１乃至請求
項３のいずれか１項記載のバリア膜製造方法であって、
前記高融点金属の窒化物薄膜を成長させる際に希釈ガス
を導入し、前記真空雰囲気の圧力を１Ｐａ以上１００Ｐ
ａ以下の範囲にすることを特徴とする。According to a fourth aspect of the present invention, there is provided the barrier film manufacturing method according to any one of the first to third aspects, wherein:
A diluent gas is introduced when growing the nitride thin film of the high melting point metal, and the pressure of the vacuum atmosphere is 1 Pa or more and 100 P or less.
a.
【００１５】請求項５記載の発明は、基板上に形成され
た高融点金属の窒化物薄膜を有し、該窒化物薄膜上に形
成された配線薄膜中の金属の拡散を防止するバリア膜で
あって、前記窒化物薄膜は、化学量論組成比よりも前記
高融点金属の含有率が大きくされたことを特徴とする。According to a fifth aspect of the present invention, there is provided a barrier film having a high melting point metal nitride thin film formed on a substrate and preventing diffusion of metal in a wiring thin film formed on the nitride thin film. The nitride thin film is characterized in that the content of the refractory metal is higher than the stoichiometric composition ratio.
【００１６】請求項６記載の発明は、基板上に形成され
た高融点金属の窒化物薄膜を有し、該窒化物薄膜上に形
成された配線薄膜中の金属の拡散を防止するバリア膜で
あって、前記窒化物薄膜は、シリコンを含まないことを
特徴とする。According to a sixth aspect of the present invention, there is provided a barrier film having a high melting point metal nitride thin film formed on a substrate and preventing diffusion of metal in a wiring thin film formed on the nitride thin film. The nitride thin film does not contain silicon.
【００１７】本発明は上記のように構成されており、真
空雰囲気中に高融点金属原子を有する原料ガスと含窒素
還元ガスを導入し、原料ガスを含窒素還元ガスで還元し
て高融点金属の窒化物を析出させる際に、真空雰囲気中
に窒素原子を含まない補助還元ガスを導入し、高融点金
属も析出するようにしている。The present invention is configured as described above. A raw material gas having a high melting point metal atom and a nitrogen-containing reducing gas are introduced into a vacuum atmosphere, and the raw material gas is reduced with the nitrogen-containing reducing gas to obtain a high melting point metal. When depositing nitride, an auxiliary reducing gas containing no nitrogen atom is introduced into a vacuum atmosphere so that a high melting point metal is also deposited.
【００１８】高融点金属の窒化物を低温で析出させた場
合、窒化物薄膜中の高融点金属が不足するが、補助還元
ガスで析出させた高融点金属原子が不足分を補充するの
で、得られる窒化物薄膜は化学量論的な組成になる。When the nitride of the refractory metal is deposited at a low temperature, the refractory metal in the nitride thin film becomes insufficient, but the refractory metal atoms deposited by the auxiliary reducing gas make up for the shortage. The resulting nitride thin film has a stoichiometric composition.
【００１９】窒化物の析出量に対し、金属の析出量は少
なくてよいが、含窒化還元ガスの反応性に比べ、補助還
元ガスの反応性は低いので、析出量に比べると多めに導
入する必要がある。The amount of metal deposited may be smaller than the amount of nitride deposited, but since the reactivity of the auxiliary reducing gas is lower than the reactivity of the nitriding-containing reducing gas, it is introduced in a larger amount than the amount of the deposited nitride. There is a need.
【００２０】他方、補助還元ガスの導入量が多すぎる
と、窒化物薄膜が形成されず、高融点金属の薄膜が形成
されてしまう。従って、含窒素還元ガスと補助還元ガス
の導入量は、適切な範囲がある。On the other hand, if the amount of the auxiliary reducing gas introduced is too large, a nitride thin film will not be formed and a thin film of a high melting point metal will be formed. Therefore, the introduction amounts of the nitrogen-containing reducing gas and the auxiliary reducing gas have an appropriate range.
【００２１】六フッ化タングステンガス(原料ガス)に対
するアンモニアガス(含窒素還元ガス)の導入量を１．０
倍、２．０倍、２．６倍に設定し、アンモニアガスに対
するシランガス(補助還元ガス)の導入量を変化させた。The introduction amount of ammonia gas (nitrogen-containing reducing gas) to tungsten hexafluoride gas (raw material gas) is set to 1.0.
, 2.0 and 2.6 times, and the introduction amount of silane gas (auxiliary reducing gas) to ammonia gas was changed.
【００２２】その結果を図３のグラフに示す。横軸は、
アンモニアガスの導入量を１．０とした場合のシランガ
スの導入量を示しており、縦軸は、形成されたタングス
テン窒化物薄膜の比抵抗を示している。The results are shown in the graph of FIG. The horizontal axis is
The amount of the silane gas introduced when the amount of the introduced ammonia gas is 1.0 is shown, and the vertical axis shows the specific resistance of the formed tungsten nitride thin film.
【００２３】このグラフから、含窒素還元ガスの導入量
は、原料ガスの導入量に対して１倍以上、補助還元ガス
の導入量は、含窒素還元ガスの導入量に対して２倍以上
１０倍以下の範囲が望ましいことが分かる。According to this graph, the introduction amount of the nitrogen-containing reducing gas is at least 1 times the introduction amount of the raw material gas, and the introduction amount of the auxiliary reducing gas is at least twice the introduction amount of the nitrogen-containing reducing gas. It can be seen that a range of less than or equal to twice is desirable.
【００２４】また、比抵抗を更に小さくしたい場合は、
このグラフから、含窒素還元ガスを原料ガスの流量に対
して１倍以上５倍以下の流量範囲で導入し、補助還元ガ
スを、含窒素還元ガスの流量に対して２倍以上５倍以下
の流量範囲で導入するとよいことが分かる。When it is desired to further reduce the specific resistance,
From this graph, the nitrogen-containing reducing gas is introduced at a flow rate range of 1 to 5 times the flow rate of the raw material gas, and the auxiliary reducing gas is supplied at a flow rate of 2 to 5 times the flow rate of the nitrogen-containing reducing gas. It can be seen that introduction in the flow rate range is good.
【００２５】図４は、本発明により、４５０℃の成膜温
度で形成したタングステン窒化物薄膜のオージェ分光分
析結果である。横軸のスパッタリング時間は表面からの
深さを示している。タングステンが多く含まれており
(窒素原子１に対し、タングステン原子は約２．６)、補
助還元ガス導入の効果が分かる。FIG. 4 shows the result of Auger spectroscopic analysis of a tungsten nitride thin film formed at a film forming temperature of 450 ° C. according to the present invention. The sputtering time on the horizontal axis indicates the depth from the surface. Contains a lot of tungsten
(Tungsten atoms are about 2.6 for one nitrogen atom), indicating the effect of introducing the auxiliary reducing gas.
【００２６】このように窒化物薄膜中の高融点金属の含
有率を、化学量論的な組成比よりも、バリア性を維持で
きる範囲で大きくすれば、比抵抗を小さくすることがで
きる。As described above, when the content of the high melting point metal in the nitride thin film is made higher than the stoichiometric composition ratio within a range where the barrier property can be maintained, the specific resistance can be reduced.
【００２７】また、窒化物薄膜中にシリコンが含まれる
と、タングステン等の高融点金属とシリコンとが高温で
反応し、タングステンシリサイド等のシリコン化合物が
生成され、比抵抗が増大してしまう。本発明の窒化物薄
膜は、シリコンを含有しないので、シリコン化合物が生
成されず、比抵抗が小さい値で安定する。Further, when silicon is contained in the nitride thin film, high-melting point metal such as tungsten reacts with silicon at a high temperature, and a silicon compound such as tungsten silicide is generated, thereby increasing the specific resistance. Since the nitride thin film of the present invention does not contain silicon, no silicon compound is generated and the specific resistance is stabilized at a small value.
【００２８】比較のため、図５に、従来技術のＣＶＤ方
法によって４５０℃の成膜温度で形成したタングステン
窒化物薄膜のオージェ分光分析結果を示す。窒素原子１
に対し、タングステン原子は約１．７であり、タングス
テン原子が少なくなっている。比抵抗も１０００μΩｃ
ｍ以上と高抵抗である。For comparison, FIG. 5 shows the results of Auger spectroscopic analysis of a tungsten nitride thin film formed at a film forming temperature of 450 ° C. by a conventional CVD method. Nitrogen atom 1
On the other hand, the number of tungsten atoms is about 1.7, and the number of tungsten atoms is small. Specific resistance is also 1000μΩc
m and high resistance.
【００２９】高融点金属の窒化物薄膜を形成するときの
圧力範囲については、１Ｐａ以上１００００Ｐａ以下が
適当であり、より好ましくは１Ｐａ以上１００Ｐａ以上
がよい。The pressure range for forming the high melting point metal nitride thin film is suitably from 1 Pa to 10,000 Pa, more preferably from 1 Pa to 100 Pa.
【００３０】 〔発明の詳細な説明〕[Detailed Description of the Invention]
【発明の属する技術分野】本発明は半導体デバイス用の
銅配線の技術分野にかかり、特に、銅配線膜と絶縁膜の
間に設けられるバリア膜の製造方法に関する。The present invention relates to the technical field of copper wiring for semiconductor devices, and more particularly, to a method of manufacturing a barrier film provided between a copper wiring film and an insulating film.
【００３１】[0031]
【発明の実施の形態】本発明の実施形態を図面を用いて
説明する。図１(ａ)〜(ｄ)は、本発明の一実施形態を示
す工程図である。Embodiments of the present invention will be described with reference to the drawings. FIGS. 1A to 1D are process diagrams showing an embodiment of the present invention.
【００３２】同図(ａ)の符号２０は、処理対象物の基板
を示している。該基板２０は、シリコン単結晶から成る
半導体基板２１を有しており、その表面には、下地膜２
２と、シリコン酸化物から成る絶縁膜２３が形成されて
いる。下地膜２２と絶縁膜２３には、底面３２に半導体
基板２１表面が露出された孔３１が形成されている。Reference numeral 20 in FIG. 3A indicates a substrate to be processed. The substrate 20 has a semiconductor substrate 21 made of silicon single crystal, and has a base film 2 on its surface.
2 and an insulating film 23 made of silicon oxide. Holes 31 are formed in the base film 22 and the insulating film 23 so that the surface of the semiconductor substrate 21 is exposed on the bottom surface 32.
【００３３】この基板２０表面に、バリア膜を形成す
る。図２を参照し、符号５０は、本発明を実施できるＣ
ＶＤ装置を示している。このＣＶＤ装置５０は真空槽５
１を有しており、該真空槽５１には、図示しない搬出入
室が接続されている。真空槽５１の底面側には基板ホル
ダ５３が配置されており、天井側には電極５５が配置さ
れている。A barrier film is formed on the surface of the substrate 20. Referring to FIG. 2, reference numeral 50 denotes a C in which the present invention can be implemented.
5 shows a VD device. This CVD device 50 is
The vacuum chamber 51 is connected to a loading / unloading chamber (not shown). A substrate holder 53 is arranged on the bottom side of the vacuum chamber 51, and an electrode 55 is arranged on the ceiling side.
【００３４】このＣＶＤ装置５０で基板２０上にバリア
膜を形成する場合、先ず、搬出入室内に基板２０を搬入
し、搬出入室及び真空槽５１内を真空雰囲気にした後、
真空槽５１と搬出入室の間のゲートバルブ５２を開け、
基板２０をＣＶＤ装置５０内に搬入する。When a barrier film is formed on the substrate 20 by the CVD apparatus 50, the substrate 20 is first loaded into the loading / unloading chamber, and the loading / unloading chamber and the vacuum chamber 51 are evacuated.
Open the gate valve 52 between the vacuum chamber 51 and the loading / unloading chamber,
The substrate 20 is carried into the CVD device 50.
【００３５】基板ホルダ５３には基板昇降機構５４が設
けられており、該基板昇降機構５４を動作させ、真空槽
５１内に搬入された基板を基板ホルダ５３上に載置す
る。図２はその状態の基板を示している。The substrate holder 53 is provided with a substrate elevating mechanism 54, and the substrate elevating mechanism 54 is operated to place the substrate carried into the vacuum chamber 51 on the substrate holder 53. FIG. 2 shows the substrate in that state.
【００３６】次いで、基板ホルダ５３内のヒータに通電
し、基板２０を３００℃以上４５０℃以下の温度に昇温
させる。Next, the heater in the substrate holder 53 is energized, and the substrate 20 is heated to a temperature of 300 ° C. or more and 450 ° C. or less.
【００３７】真空槽５１にはガス導入系５７が設けられ
ており、そのガス導入系５７からアルゴンガスとアンモ
ニアガスを所定流量で真空槽５１内に導入し、基板ホル
ダ５３と電極５５の間に高周波電圧を印加すると、アン
モニアガスから電離状態の窒素と水素が生成される。こ
のとき、電離したアルゴンガスは希釈ガスとなりそれら
が混合したプラズマが形成される。A gas introduction system 57 is provided in the vacuum chamber 51. Argon gas and ammonia gas are introduced into the vacuum chamber 51 at a predetermined flow rate from the gas introduction system 57, and the gas is introduced between the substrate holder 53 and the electrode 55. When a high-frequency voltage is applied, ionized nitrogen and hydrogen are generated from the ammonia gas. At this time, the ionized argon gas becomes a diluent gas, and a plasma in which these gases are mixed is formed.
【００３８】基板２０表面の絶縁膜２３は電極５５に近
接して対向配置されており、生成されたプラズマによ
り、絶縁膜２３表面、孔３１内の半導体基板２１表面が
その混合プラズマに曝され、付着していた有機物が分解
される(クリーニング)。The insulating film 23 on the surface of the substrate 20 is disposed in close proximity to the electrode 55, and the surface of the insulating film 23 and the surface of the semiconductor substrate 21 in the hole 31 are exposed to the mixed plasma by the generated plasma. The attached organic matter is decomposed (cleaning).
【００３９】ここでのクリーニング条件は、アンモニア
ガス流量１００ｓｃｃｍ、アルゴンガス流量３００ｓｃ
ｃｍ、圧力４０Ｐａ、高周波電力１００Ｗとした。１５
秒間程度のクリーニングを行った後、高周波電圧の印加
を停止し、プラズマを消滅させる。The cleaning conditions were as follows: ammonia gas flow rate 100 sccm, argon gas flow rate 300 sccm
cm, pressure 40 Pa, high frequency power 100 W. Fifteen
After cleaning for about 2 seconds, application of the high-frequency voltage is stopped to extinguish the plasma.
【００４０】次いで、上記アンモニアガス流量及びアル
ゴンガス流量を変えると共に、アンモニアガスとアルゴ
ンガスに加え、ガス導入系５７から真空槽５１内に六フ
ッ化タングステンガス(ＷＦ6ガス)とシランガスを導入
する。Next, while changing the ammonia gas flow rate and the argon gas flow rate, in addition to the ammonia gas and the argon gas, a tungsten hexafluoride gas (WF 6 gas) and a silane gas are introduced into the vacuum chamber 51 from the gas introduction system 57. .
【００４１】アンモニアガスの反応性はシランガスに比
べて高いので、六フッ化タングステンガスが原料ガス、
アンモニアガスが含窒素還元ガスとなり、原料ガスの還
元反応が進行する。アンモニアガスは窒素を有している
ので、上記(１)式のような還元反応により、絶縁膜２３
表面及び孔３１内の半導体基板２１表面にタングステン
窒化物が析出する。Since the reactivity of ammonia gas is higher than that of silane gas, tungsten hexafluoride gas is
The ammonia gas becomes the nitrogen-containing reducing gas, and the reduction reaction of the raw material gas proceeds. Since the ammonia gas has nitrogen, the insulating film 23 is subjected to a reduction reaction as in the above equation (1).
Tungsten nitride precipitates on the surface and the surface of the semiconductor substrate 21 in the hole 31.
【００４２】真空槽５１内に導入されたシランガスも還
元性を有しているが、アンモニアガスに比べて反応性は
低いので、補助的な還元ガス(補助還元ガス)となる。ま
た、シランガスは窒素原子を有していないので、下記
(３)式のような反応で原料ガスを還元し、金属タングス
テンを析出させる。 ＷＦ6＋３／２ ＳｉＨ4 → Ｗ＋３／２ ＳｉＦ4＋３Ｈ2 ……(３)The silane gas introduced into the vacuum chamber 51 also has a reducing property, but since it is less reactive than the ammonia gas, it becomes an auxiliary reducing gas (auxiliary reducing gas). Also, since silane gas does not have a nitrogen atom,
The raw material gas is reduced by the reaction shown in the equation (3) to deposit metal tungsten. WF 6 +3/2 SiH 4 → W + 3/2 SiF 4 + 3H 2 (3)
【００４３】金属タングステンが析出すると、成長中の
タングステン窒化物薄膜内に取り込まれる。従って、タ
ングステンの窒化物薄膜の成長中に、金属タングステン
が供給されるので、低温で成長する場合のタングステン
の不足分が補償され、化学量論組成に近似したバリア膜
(窒化タングステン薄膜)が形成される。When the metal tungsten is deposited, it is taken into the growing tungsten nitride thin film. Therefore, since tungsten is supplied during the growth of the tungsten nitride thin film, the shortage of tungsten when growing at a low temperature is compensated, and the barrier film having a stoichiometric composition is compensated.
(Tungsten nitride thin film) is formed.
【００４４】タングステンの窒化物薄膜の成長条件の一
例としては、基板温度３８０℃、原料ガス流量５ｓｃｃ
ｍ、含窒素還元ガス流量を１３ｓｃｃｍ、補助還元ガス
流量７２ｓｃｃｍ、圧力４０Ｐａである。As an example of the growth conditions of the tungsten nitride thin film, the substrate temperature is 380 ° C., and the raw material gas flow rate is 5 scc.
m, the flow rate of the nitrogen-containing reducing gas is 13 sccm, the flow rate of the auxiliary reducing gas is 72 sccm, and the pressure is 40 Pa.
【００４５】含窒素還元ガス及び補助還元ガスによる原
料ガスの還元反応を所定時間行うと、図１(ｂ)の符号２
４に示すように、絶縁膜２３及び半導体基板２１表面に
タングステンの窒化物薄膜が形成される。When the reduction reaction of the raw material gas with the nitrogen-containing reducing gas and the auxiliary reducing gas is performed for a predetermined time, a reference numeral 2 in FIG.
As shown in FIG. 4, a tungsten nitride thin film is formed on the surfaces of the insulating film 23 and the semiconductor substrate 21.
【００４６】次いで、含窒素還元ガスの導入を停止し、
補助還元性ガスの流量を増加させると、補助還元性ガス
によって原料ガスが還元され、金属タングステンが析出
する。図１(ｃ)の符号２５は、窒化物薄膜２４表面に成
長した金属タングステン薄膜を示している。Next, the introduction of the nitrogen-containing reducing gas is stopped,
When the flow rate of the auxiliary reducing gas is increased, the source gas is reduced by the auxiliary reducing gas, and metal tungsten is deposited. Reference numeral 25 in FIG. 1C indicates a metal tungsten thin film grown on the surface of the nitride thin film 24.
【００４７】金属タングステン薄膜２５の形成条件の一
例としては、基板温度３８０℃、原料ガス導入量２０ｓ
ｃｃｍ、補助還元ガス導入量５ｓｃｃｍ、希釈ガス(ア
ルゴンガス)導入量２４０ｓｃｃｍ、圧力４０Ｐａであ
る。As an example of the conditions for forming the metal tungsten thin film 25, the substrate temperature is 380 ° C., and the raw material gas introduction amount is 20 seconds.
ccm, the introduction amount of the auxiliary reducing gas is 5 sccm, the introduction amount of the diluent gas (argon gas) is 240 sccm, and the pressure is 40 Pa.
【００４８】窒化物薄膜２４は銅に対する高いバリア性
を有しているが、高融点金属に比べると比抵抗が高い。
他方、金属タングステン薄膜２５等の高融点金属の薄膜
は、銅に対するバリア性は低いものの、比抵抗は窒化物
薄膜２４よりも非常に小さい。The nitride thin film 24 has a high barrier property against copper, but has a higher specific resistance than a high melting point metal.
On the other hand, a high-melting-point metal thin film such as the metal tungsten thin film 25 has a low barrier property against copper, but has a much lower specific resistance than the nitride thin film 24.
【００４９】従って、上記のように窒化物薄膜２４をバ
リア膜とし、その上に高融点金属薄膜を積層させると、
銅に対する高いバリア性を維持したまま、比抵抗を小さ
くすることができる。Therefore, as described above, when the nitride thin film 24 is used as a barrier film and a refractory metal thin film is laminated thereon,
The specific resistance can be reduced while maintaining a high barrier property against copper.
【００５０】上記の条件でタングステン薄膜２５を２０
〜３０秒間成長させた後、基板２０をＣＶＤ装置５０の
外部に搬出し、メッキ法やスパッタリング法等により、
高融点金属薄膜２５表面に銅薄膜を成長させる。図１
(ｄ)の符号２６は、その銅薄膜を示している。Under the above conditions, the tungsten thin film 25 is
After growing for ~ 30 seconds, the substrate 20 is carried out of the CVD apparatus 50, and is subjected to a plating method, a sputtering method, or the like.
A copper thin film is grown on the surface of the high melting point metal thin film 25. FIG.
Reference numeral 26 in (d) indicates the copper thin film.
【００５１】最後に、ＣＭＰ法によって表面研磨し、絶
縁膜２３上の銅薄膜２６及び窒化物薄膜２４と金属薄膜
２５とを研磨除去すると、孔３１内に銅配線２７が形成
される。その銅配線２７と半導体基板２１の間、及び絶
縁膜２３の間には窒化物薄膜２４が存しており、銅が拡
散しないようになっている。Finally, the surface is polished by the CMP method, and the copper thin film 26, the nitride thin film 24 and the metal thin film 25 on the insulating film 23 are polished and removed. As a result, a copper wiring 27 is formed in the hole 31. A nitride thin film 24 exists between the copper wiring 27 and the semiconductor substrate 21 and between the insulating film 23 so that copper does not diffuse.
【００５２】以上は高融点金属にタングステン、含窒素
還元ガスにアンモニアガス、補助還元ガスにシランガス
を用い、タングステンの窒化物薄膜を形成する場合を説
明したが、原料ガスには六フッ化タングステンガスの
他、Ｗ(ＣＯ)6ガスを用いることができる。The above description has been made on the case where a tungsten nitride thin film is formed by using tungsten as a high melting point metal, ammonia gas as a nitrogen-containing reducing gas, and silane gas as an auxiliary reducing gas. In addition, W (CO) 6 gas can be used.
【００５３】また、タングステン以外の高融点金属を用
い、それらの窒化物薄膜をバリア膜として形成する場合
も本発明に含まれる。チタン(Ｔｉ)を高融点金属に用い
る場合は、ＴｉＦ4やＴｉＣｌ4等のチタンハライドガス
を原料ガスにすることができる。タンタル(Ｔａ)を高融
点金属に用いる場合は、ＴａＣｌ5等のタンタルハライ
ドガス等を原料ガスにすることができる。The present invention also includes a case where a high melting point metal other than tungsten is used and a nitride thin film thereof is formed as a barrier film. When titanium (Ti) is used as the refractory metal, a titanium halide gas such as TiF 4 or TiCl 4 can be used as a source gas. When tantalum (Ta) is used as the high melting point metal, a tantalum halide gas such as TaCl 5 can be used as a source gas.
【００５４】窒素原子を有する含窒素還元ガスには、Ｎ
Ｈ3ガスの他、Ｎ2Ｈ4ガス、ＮＦ3ガス、Ｎ2Ｏガス等を
用いることができる。The nitrogen-containing reducing gas having a nitrogen atom includes N
In addition to H 3 gas, N 2 H 4 gas, NF 3 gas, N 2 O gas and the like can be used.
【００５５】窒素原子を有さない補助還元ガスとして
は、ＳｉＨ4ガスの他、Ｈ2ガス、Ｓｉ 2Ｈ6ガス、ＰＨ3
ガス、Ｂ2Ｈ6ガス等を用いることができる。As an auxiliary reducing gas having no nitrogen atom,
Is SiHFourIn addition to gas, HTwoGas, Si TwoH6Gas, PHThree
Gas, BTwoH6Gas or the like can be used.
【００５６】[0056]
【発明の効果】ＣＶＤ法により、５００℃以下、特に３
５０℃〜４５０℃の温度範囲で低比抵抗のバリア膜(高
融点金属の窒化物薄膜)を形成できる。従って、層間絶
縁膜にダメージを与えることがない。また、熱ＣＶＤ法
で窒化物薄膜を形成するので、ステップカバレッジが良
好である。EFFECTS OF THE INVENTION By the CVD method, 500 ° C. or less, especially 3 ° C.
A low resistivity barrier film (a nitride thin film of a high melting point metal) can be formed in a temperature range of 50 ° C. to 450 ° C. Therefore, no damage is given to the interlayer insulating film. Further, since the nitride thin film is formed by the thermal CVD method, the step coverage is good.
【図１】(ａ)〜(ｅ)：本発明方法を説明するための工程
図FIG. 1 (a) to (e): process charts for explaining the method of the present invention.
【図２】本発明方法を実施できるＣＶＤ装置の一例FIG. 2 shows an example of a CVD apparatus capable of performing the method of the present invention.
【図３】本発明方法により形成したタングステン窒化物
薄膜の比抵抗と、原料ガス、含窒素還元ガス、及び補助
還元ガスの流量との関係を示すグラフFIG. 3 is a graph showing the relationship between the specific resistance of a tungsten nitride thin film formed by the method of the present invention and the flow rates of a source gas, a nitrogen-containing reducing gas, and an auxiliary reducing gas.
【図４】本発明方法により形成したタングステン窒化物
の深さ方向の組成を示すグラフFIG. 4 is a graph showing the composition in the depth direction of tungsten nitride formed by the method of the present invention.
【図５】従来技術のタングステン窒化物の深さ方向の組
成を示すグラフFIG. 5 is a graph showing the composition in the depth direction of a conventional tungsten nitride.
２０……基板 ２４……窒化物薄膜(バリア膜) ２
５……金属薄膜20: substrate 24: nitride thin film (barrier film) 2
5 Metal thin film
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4M104 BB33 CC01 DD45 DD64 DD75 FF16 FF22 5F033 HH11 HH18 HH19 HH21 HH32 HH33 HH34 KK01 LL10 MM01 MM12 MM13 PP02 PP04 PP06 PP15 PP27 QQ37 QQ48 QQ92 QQ96 RR04 TT01 WW05 WW06 XX02 XX10 XX28 XX33 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4M104 BB33 CC01 DD45 DD64 DD75 FF16 FF22 5F033 HH11 HH18 HH19 HH21 HH32 HH33 HH34 KK01 LL10 MM01 MM12 MM13 PP02 PP04 PP06 PP15 PP27 QQ37 QQ48 XX04 XXXXX XX04 XXXXX
Claims (6)
と、窒素原子を有する含窒素還元ガスとを真空雰囲気中
に導入し前記真空雰囲気中に置かれた基板上に前記高融
点金属の窒化物薄膜を形成するバリア膜製造方法であっ
て、 前記真空雰囲気中に、窒素原子を有さない補助還元ガス
を導入することを特徴とするバリア膜製造方法。1. A high-melting-point metal source gas having a chemical structure and a nitrogen-containing reducing gas having a nitrogen atom are introduced into a vacuum atmosphere, and said high-melting-point metal is deposited on a substrate placed in said vacuum atmosphere. A method for manufacturing a barrier film for forming a nitride thin film, comprising introducing an auxiliary reducing gas having no nitrogen atom into the vacuum atmosphere.
量に対して１倍以上の流量で導入し、前記補助還元ガス
を、前記含窒素還元ガスの流量に対して１倍以上１０倍
以下の流量で導入することを特徴とする請求項１記載の
バリア膜製造方法。2. The nitrogen-containing reducing gas is introduced at a flow rate of at least 1 times the flow rate of the raw material gas, and the auxiliary reducing gas is at least 1-fold to 10 times the flow rate of the nitrogen-containing reducing gas. The method for producing a barrier film according to claim 1, wherein the introduction is performed at the following flow rate.
量に対して１倍以上５倍以下の流量で導入し、前記補助
還元ガスを、前記含窒素還元ガスの流量に対して２倍以
上１０倍以下の流量で導入することを特徴とする請求項
１記載のバリア膜製造方法。3. The nitrogen-containing reducing gas is introduced at a flow rate of 1 to 5 times the flow rate of the raw material gas, and the auxiliary reducing gas is twice as large as the flow rate of the nitrogen-containing reducing gas. The method for producing a barrier film according to claim 1, wherein the introduction is performed at a flow rate of at least 10 times or less.
際に希釈ガスを導入し、前記真空雰囲気の圧力を１Ｐａ
以上１００Ｐａ以下の範囲にすることを特徴とする請求
項１乃至請求項３のいずれか１項記載のバリア膜製造方
法。4. A method for introducing a diluting gas when growing the nitride thin film of the refractory metal, and adjusting the pressure of the vacuum atmosphere to 1 Pa
The barrier film manufacturing method according to any one of claims 1 to 3, wherein the pressure is in a range of not less than 100 Pa and not more than 100 Pa.
膜を有し、該窒化物薄膜上に形成された配線薄膜中の金
属の拡散を防止するバリア膜であって、 前記窒化物薄膜は、化学量論組成比よりも前記高融点金
属の含有率が大きくされたことを特徴とするバリア膜。5. A barrier film having a refractory metal nitride thin film formed on a substrate, wherein the barrier film prevents diffusion of a metal in a wiring thin film formed on the nitride thin film. A barrier film, wherein the thin film has a higher content of the high melting point metal than a stoichiometric composition ratio.
膜を有し、該窒化物薄膜上に形成された配線薄膜中の金
属の拡散を防止するバリア膜であって、 前記窒化物薄膜は、シリコンを含まないことを特徴とす
るバリア膜。6. A barrier film having a high melting point metal nitride thin film formed on a substrate, wherein the barrier film prevents diffusion of metal in a wiring thin film formed on the nitride thin film, A barrier film, wherein the thin film does not contain silicon.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03804199A JP4009034B2 (en) | 1999-02-17 | 1999-02-17 | Barrier film manufacturing method |
| KR1020000006214A KR100773280B1 (en) | 1999-02-17 | 2000-02-10 | Barrier film and method of manufacturing the same |
| TW089102530A TW451357B (en) | 1999-02-17 | 2000-02-15 | Manufacturing method of barrier film and the barrier film |
| EP00103073A EP1029943B1 (en) | 1999-02-17 | 2000-02-15 | Process for producing barrier film |
| DE60019660T DE60019660T2 (en) | 1999-02-17 | 2000-02-15 | Method for applying a barrier layer |
| US09/504,923 US6743718B1 (en) | 1999-02-17 | 2000-02-16 | Process for producing barrier film and barrier film thus produced |
| US10/133,432 US20020123215A1 (en) | 1999-02-17 | 2002-04-29 | Process for producing barrier film and barrier film thus produced |
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|---|---|---|---|
| JP03804199A JP4009034B2 (en) | 1999-02-17 | 1999-02-17 | Barrier film manufacturing method |
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| JP2007163880A Division JP2007251211A (en) | 2007-06-21 | 2007-06-21 | Method of fabricating barrier film and barrier film |
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|---|---|
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| JP2000235963A5 JP2000235963A5 (en) | 2005-11-04 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001156024A (en) * | 1999-09-13 | 2001-06-08 | Tokyo Electron Ltd | TiN-BASED THIN FILM AND FILM-FORMING METHOD THEREFOR, FILM-FORMING APPARATUS, FILM STRUCTURAL BODY INCLUDING TiN-BASED THIN FILM AND MANUFACTURING METHOD THEREFOR, AND SEMICONDUCTOR DEVICE |
| JP2006028572A (en) * | 2004-07-14 | 2006-02-02 | Ulvac Japan Ltd | Thin film deposition method |
| CN108511389A (en) * | 2017-02-28 | 2018-09-07 | 东京毅力科创株式会社 | Semiconductor making method and plasma processing apparatus |
-
1999
- 1999-02-17 JP JP03804199A patent/JP4009034B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001156024A (en) * | 1999-09-13 | 2001-06-08 | Tokyo Electron Ltd | TiN-BASED THIN FILM AND FILM-FORMING METHOD THEREFOR, FILM-FORMING APPARATUS, FILM STRUCTURAL BODY INCLUDING TiN-BASED THIN FILM AND MANUFACTURING METHOD THEREFOR, AND SEMICONDUCTOR DEVICE |
| JP2006028572A (en) * | 2004-07-14 | 2006-02-02 | Ulvac Japan Ltd | Thin film deposition method |
| JP4674061B2 (en) * | 2004-07-14 | 2011-04-20 | 株式会社アルバック | Thin film formation method |
| CN108511389A (en) * | 2017-02-28 | 2018-09-07 | 东京毅力科创株式会社 | Semiconductor making method and plasma processing apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4009034B2 (en) | 2007-11-14 |
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