JP2007173610A - Method for measuring film characteristic and sample for film characteristic measurement - Google Patents

Method for measuring film characteristic and sample for film characteristic measurement Download PDF

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JP2007173610A
JP2007173610A JP2005370649A JP2005370649A JP2007173610A JP 2007173610 A JP2007173610 A JP 2007173610A JP 2005370649 A JP2005370649 A JP 2005370649A JP 2005370649 A JP2005370649 A JP 2005370649A JP 2007173610 A JP2007173610 A JP 2007173610A
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film
measuring
characteristic
measurement
elastic modulus
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Koji Sumiya
孝治 住谷
Toshio Murata
敏夫 村田
Kazuhiro Koga
和博 古賀
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CONSORTIUM ADVANCED SEMICONDUCTOR MATERIALS & RELATED TECHNOLOGIES
CONSORTIUM FOR ADVANCED SEMICONDUCTOR MATERIALS &RELATED TECHNOLOGIES
Consortium for Advanced Semiconductor Materials and Related Technologies
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CONSORTIUM ADVANCED SEMICONDUCTOR MATERIALS & RELATED TECHNOLOGIES
CONSORTIUM FOR ADVANCED SEMICONDUCTOR MATERIALS &RELATED TECHNOLOGIES
Consortium for Advanced Semiconductor Materials and Related Technologies
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<P>PROBLEM TO BE SOLVED: To provide a technology capable of accurately obtaining physical properties, specifically an elastic modulus acting as a benchmark for an exfoliation and damage of a Low-k film having a thickness of tens to hundreds nm, and of obtaining quantitative information regarding a rate of occurrence (the exfoliation and damage of the film) of defects in a CMP process and a wirebonding process. <P>SOLUTION: A method for measuring the film characteristic comprises the steps of film forming a composite film in providing a film B that is harder than the film A on the film A, and after the film forming step, measuring the characteristic of the composite film from over the film B. The method for measuring the film characteristic calculates the characteristics of the film A at the time of zero thickness of the film B in conducting the same steps for several thickness of the film B. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、例えば半導体ウェハのCMP(化学・機械研磨)工程やワイヤーボンディング工程における半導体ウェハの膜剥離や膜破壊、特に、低誘電率絶縁膜、所謂、Low−k膜の特性を測定する為の技術に関する。   The present invention is for measuring film characteristics and film breakdown of a semiconductor wafer, particularly in a low dielectric constant insulating film, so-called low-k film, for example in a CMP (chemical / mechanical polishing) process or wire bonding process of a semiconductor wafer. Related to technology.

半導体デバイスにおける演算処理速度の高速化を実現する為には、デバイスにおける信号遅延を低減することが重要である。この信号遅延は、半導体素子における信号遅延と配線遅延の和で表される。ところで、近年、配線ピッチの微細化が急速に進んでいる。この為、配線遅延の影響が信号遅延を上回るようになって来た。この配線遅延は、配線抵抗Rと配線間容量Cとの積、所謂、RCに比例する。従って、配線遅延を低減する為、配線抵抗や配線間容量を低減する必要がある。このようなことから、配線材料として、低抵抗なCuが選ばれるようになった。又、配線間を埋める絶縁材として、低誘電率絶縁材(Low−k材)の検討が行なわれている。   In order to increase the calculation processing speed in a semiconductor device, it is important to reduce the signal delay in the device. This signal delay is represented by the sum of the signal delay and the wiring delay in the semiconductor element. By the way, in recent years, miniaturization of the wiring pitch is rapidly progressing. For this reason, the influence of wiring delay has exceeded the signal delay. This wiring delay is proportional to the product of the wiring resistance R and the inter-wiring capacitance C, so-called RC. Therefore, in order to reduce wiring delay, it is necessary to reduce wiring resistance and wiring capacity. For this reason, low resistance Cu has been selected as a wiring material. Further, a low dielectric constant insulating material (Low-k material) has been studied as an insulating material that fills between the wirings.

さて、誘電率を小さくする為、膜内部にポア(空孔)を導入したり、極性の大きいフッ素を導入することが考えられている。特に、ポアを導入する手法が盛んに研究され、比誘電率が2.5以下のものも実現されている。   In order to reduce the dielectric constant, it has been considered to introduce pores (holes) inside the film or introduce fluorine having a large polarity. In particular, methods for introducing pores have been actively studied, and a dielectric constant of 2.5 or less has been realized.

しかしながら、ポア構造の膜は、その機械的強度が弱い。かつ、これに伴って、ポア構造膜と該ポア構造膜の上・下膜との密着性が低下していることが判ってきた。   However, the pore structure film has a low mechanical strength. Along with this, it has been found that the adhesion between the pore structure film and the upper and lower films of the pore structure film is lowered.

ところが、このことは大きな問題である。すなわち、上記のような膜であった場合、即ち、上記特性のようなポア構造膜が配線間絶縁膜として採用された場合、例えば配線膜形成工程、特に、CMP工程やパッケージ工程において膜剥離や膜損傷が起き易く、中でも、ワイヤーボンディング工程では、膜剥離が起き易いことが判って来た。   However, this is a big problem. That is, when the film is as described above, that is, when the pore structure film having the above characteristics is adopted as the inter-wiring insulating film, for example, in the wiring film forming process, particularly in the CMP process and the packaging process, It has been found that film damage is likely to occur, and in particular, film peeling is likely to occur in the wire bonding process.

そこで、ポア構造膜(Low−k膜)の機械的強度についての検討が十分になされなければならないものの、その評価を如何すれば良いかが確立されていない。   Therefore, although the mechanical strength of the pore structure film (Low-k film) has to be sufficiently studied, it has not been established how to evaluate the mechanical structure.

尚、例えば特開2001−349815号公報に単一材料の薄膜の物性(弾性率)測定方法が提案されている。すなわち、ナノインデンテーション法を用いて弾性率を測定することが提案されている。この提案によれば、薄膜の弾性率の高精度化を目的として、それなりの効果が奏されているようである。
特開2001−349815号公報
For example, Japanese Patent Application Laid-Open No. 2001-349815 proposes a method for measuring physical properties (elastic modulus) of a single material thin film. That is, it has been proposed to measure the elastic modulus using the nanoindentation method. According to this proposal, there seems to be a certain effect for the purpose of increasing the accuracy of the elastic modulus of the thin film.
JP 2001-349815 A

しかしながら、比誘電率が3以下のLow−k膜の弾性率を求めようとした場合、特に、実際の配線間絶縁膜として用いられている如きの薄膜でのLow−k膜の弾性率を求めようとした場合、その機械的強度は非常に弱い。従って、ナノインデンテーション法による硬度や弾性率測定時の接触端子の押し込みにより、膜自身が変形してしまい、その結果、押し込み時の表面位置の検出が困難となり、測定データが不明瞭になってしまうことが判って来た。   However, when the elastic modulus of a low-k film having a relative dielectric constant of 3 or less is to be obtained, the elastic modulus of the low-k film in a thin film such as an actual inter-wiring insulating film is obtained. In such a case, the mechanical strength is very weak. Therefore, the film itself deforms due to the pressing of the contact terminal when measuring hardness and elastic modulus by the nanoindentation method. As a result, it becomes difficult to detect the surface position at the time of pressing, and the measurement data becomes unclear. I have come to understand.

かつ、比誘電率が3以下のLow−k膜は、実デバイスにおいて使用される膜厚が300nm以下と薄い。従って、このような厚さの薄膜をシリコン基板上に成膜してナノインデンテーション法による評価を行なった場合、実は、下地である硬度の高いシリコン基板の影響を強く受けており、数値が真実の値から離れているようであることも判って来た。すなわち、数値に信頼性が欠けていることが判って来た。   In addition, the low-k film having a relative dielectric constant of 3 or less has a thin film thickness of 300 nm or less used in an actual device. Therefore, when a thin film with such a thickness is deposited on a silicon substrate and evaluated by the nanoindentation method, it is actually strongly influenced by the hard silicon substrate that is the base, and the numerical value is true. It has also been found that it seems to be far from the value of. In other words, it has been found that the numerical values are not reliable.

従って、本発明が解決しようとする課題は、正しい物性値が得られる技術を提供することである。特に、配線間絶縁膜としてのLow−k膜の剥離性や損傷度の評価基準となる物性、特に、弾性率を正確に求められる技術を提供することである。中でも、数十〜数百nm厚と言ったLow−k膜の剥離性や損傷度の評価基準となる物性、特に、弾性率を正確に求められる技術を提供することである。そして、半導体デバイスにおける配線間絶縁膜の材料開発において非常に役立つ情報が簡便に得られ、特に、CMP工程やワイヤーボンディング工程における不良品の発生率(膜の剥離や損傷)に関する定量的な情報が得られるようになる技術を提供することである。   Therefore, the problem to be solved by the present invention is to provide a technique capable of obtaining correct physical property values. In particular, it is to provide a technique capable of accurately obtaining physical properties, in particular, elastic modulus, which are evaluation criteria for peelability and damage degree of a low-k film as an inter-wiring insulating film. Among other things, it is to provide a technique that can accurately determine physical properties, in particular, elastic modulus, which are evaluation criteria for peelability and damage degree of a Low-k film having a thickness of several tens to several hundreds nm. Information that is very useful in the development of materials for inter-wiring insulating films in semiconductor devices can be easily obtained. In particular, quantitative information on the rate of defective products (film peeling and damage) in the CMP process and wire bonding process can be obtained. It is to provide the technology that becomes available.

前記課題についての検討が本発明者によって鋭意推し進められて行く中に、数十〜数百nm厚と言ったLow−k膜(A)の上に高硬度な膜(B)を積層し、そしてナノインデンテーション法による評価を行なった場合、この場合には複合膜(A+B)の弾性率が得られ、かつ、測定対象は複合膜(A+B)であるからLow−k膜(A)が薄膜であるが故の問題点は無いであろうこと、そしてこのような複合膜におけるB膜の厚さを幾つか変えた場合に得た弾性率とB膜の厚さとは或る関数関係に有るのでは無いかとの啓示を得るに至り、そうであるならば外挿法によってB膜が0の場合、即ち、数十〜数百nm厚の薄膜であるLow−k膜(A)の弾性率が得られるのでは無いかと考えるに至った。   While the inventor has eagerly pursued the study on the above-mentioned problem, a high-hardness film (B) is laminated on the Low-k film (A) having a thickness of several tens to several hundreds of nm, and In the case of evaluation by the nanoindentation method, the elastic modulus of the composite film (A + B) is obtained in this case, and the measurement object is the composite film (A + B), so the Low-k film (A) is a thin film. There is no problem because of this, and there is a certain functional relationship between the elastic modulus obtained when the thickness of the B film in such a composite film is changed and the thickness of the B film. If so, if the B film is zero by extrapolation, that is, the elastic modulus of the Low-k film (A), which is a thin film of several tens to several hundreds of nm, It came to think that it might be obtained.

すなわち、Si基板上に設けたLow−k薄膜の強度を測定するに際して、十分な硬度や弾性率を有するキャップ膜を積層して測定した場合、Low−k薄膜の上層のキャップ膜は測定端子との接触で変形することが無く、測定のスタートポイントが明らかであり、かつ、キャップ膜による硬度や弾性率の影響は測定端子が圧子として材料に侵入するに伴って影響度を変え、その影響量が最小になるであろうとの啓示を得るに至ったのである。   That is, when measuring the strength of the low-k thin film provided on the Si substrate and measuring a laminated cap film having sufficient hardness and elastic modulus, the upper cap film of the low-k thin film is The measurement start point is clear, and the influence of hardness and elastic modulus due to the cap film changes the degree of influence as the measuring terminal enters the material as an indenter, and the amount of influence It came to a revelation that would be minimized.

そして、この考えに基づいて数十〜数百nm厚のLow−k膜(A)の弾性率を求め、又、この弾性率についての検証を行った処、上記技術思想が正しいものであることの裏付けが得られた。   Based on this idea, the elastic modulus of the low-k film (A) having a thickness of several tens to several hundreds of nanometers (A) is obtained, and when the elastic modulus is verified, the above technical idea is correct. The support of was obtained.

上記知見に基づいて本発明が達成されたものである。
すなわち、前記の課題は、膜Aの特性を測定する方法であって、
膜Aの上に設けられた該膜Aより高硬度な膜Bの上から膜強度を測定する
ことを特徴とする膜特性測定方法によって解決される。
The present invention has been achieved based on the above findings.
That is, the above-mentioned problem is a method for measuring the characteristics of the film A,
This is solved by a film characteristic measuring method characterized in that the film strength is measured from above the film B having a higher hardness than the film A provided on the film A.

又、膜Aの特性を測定する方法であって、
膜Aよりも高硬度な膜Bを該膜Aの上に設けて複合膜を形成する成膜工程と、
前記成膜工程の後、前記膜B上から該複合膜の特性を測定する測定工程
とを具備することを特徴とする膜特性測定方法によって解決される。
Also, a method for measuring the characteristics of the film A,
A film forming step in which a film B having a hardness higher than that of the film A is provided on the film A to form a composite film;
After the film forming step, the method is solved by a film characteristic measuring method comprising a measuring step of measuring the characteristic of the composite film from the film B.

又、膜Aの特性を測定する方法であって、
膜Aよりも高硬度な膜Bを該膜Aの上に設けて複合膜を形成する成膜工程、及び前記成膜工程の後で前記膜B上から該複合膜の特性を測定する測定工程を具備し、
前記膜Bの厚さが幾つかの場合において同様に行って膜Bの厚さが0の場合における膜Aの特性を算出することを特徴とする膜特性測定方法によって解決される。
Also, a method for measuring the characteristics of the film A,
A film forming step for forming a composite film by providing a film B having a higher hardness than the film A on the film A, and a measuring step for measuring the characteristics of the composite film from the film B after the film forming step. Comprising
This is solved by a film characteristic measuring method characterized by calculating the characteristics of the film A when the thickness of the film B is 0 when the thickness of the film B is several.

上記膜特性測定方法は、特に、圧子が膜に押込まれることで測定が行われる膜特性測定方法である。更には、圧子が膜に10nm〜200nmの深さ押込まれることで測定が行われる膜特性測定方法である。中でも、ナノインデンテーション法によって測定が行われる膜特性測定方法である。   The above-mentioned film characteristic measurement method is a film characteristic measurement method in which measurement is performed particularly when an indenter is pushed into the film. Furthermore, it is a film | membrane characteristic measurement method in which a measurement is performed when an indenter is pushed into the film by a depth of 10 nm to 200 nm. Especially, it is a film | membrane characteristic measuring method in which a measurement is performed by the nanoindentation method.

本発明において、膜Aの上に積層される膜Bは、膜Aの硬度よりも高硬度なものであれば良いが、特に、弾性率が10GPa以上のものが好ましい。中でも、20GPa以上のものが好ましい。上限値に格別な制約は無いが、現実的には、70GPa程度のものである。   In the present invention, the film B laminated on the film A may be one having a hardness higher than the hardness of the film A, and in particular, one having an elastic modulus of 10 GPa or more is preferable. Of these, those of 20 GPa or more are preferable. Although there is no particular restriction on the upper limit value, it is practically about 70 GPa.

本発明において、膜Aは、基本的には、如何なるものであっても良い。しかしながら、硬度が高いものであれば、本発明の手法を用いずとも、それなりに正確な物性が得られる。本発明の手法を採用しなければ正しい物性値が得られないのは、内部がポア構造の膜の場合である。すなわち、比誘電率が3以下のものである。特に、比誘電率が2.5以下のものである。下限値に格別な制約は無いが、比誘電率は1より大きいものである。更に、厚さが10〜1000nm(特に、30nm以上、200nm以下。)のものである。   In the present invention, the film A may be basically any type. However, if the hardness is high, accurate physical properties can be obtained without using the method of the present invention. If the method of the present invention is not employed, correct physical property values cannot be obtained in the case of a film having a pore structure. That is, the relative dielectric constant is 3 or less. In particular, the relative dielectric constant is 2.5 or less. Although there is no particular restriction on the lower limit value, the relative dielectric constant is larger than 1. Furthermore, the thickness is 10 to 1000 nm (particularly, 30 nm or more and 200 nm or less).

本発明において、膜Aと膜Bとの複合膜は、その厚さが0.1〜1μm程度であることが好ましい。   In the present invention, the composite film of the film A and the film B preferably has a thickness of about 0.1 to 1 μm.

又、前記の課題は、膜Aの特性を測定する為に用いられる測定用試料であって、
膜Aの上に該膜Aより高硬度な膜Bが設けられたものである
ことを特徴とする膜特性測定用試料によって解決される。
The above-mentioned problem is a measurement sample used for measuring the characteristics of the film A,
This is solved by a film characteristic measurement sample characterized in that a film B having a hardness higher than that of the film A is provided on the film A.

特に、上記の膜特性測定方法に用いられる測定用試料であって、
膜Aの上に該膜Aより高硬度な膜Bが設けられたものである
ことを特徴とする膜特性測定用試料によって解決される。
In particular, a measurement sample used in the above-described method for measuring film characteristics,
This is solved by a film characteristic measurement sample characterized in that a film B having a hardness higher than that of the film A is provided on the film A.

特に、膜Aの上に積層される膜Bは、膜Aの硬度より高硬度なことを要件とするが、特に、弾性率が10GPa以上のものが好ましいが、20GPa以上のものが中でも特に好ましい。上限値に格別な制約は無いが、現実的には、70GPa程度のものである。   In particular, the film B laminated on the film A is required to have a hardness higher than the hardness of the film A. In particular, the elastic modulus is preferably 10 GPa or more, and particularly preferably 20 GPa or more. . Although there is no particular restriction on the upper limit value, it is practically about 70 GPa.

膜Aは、特に、比誘電率が3以下のものである。特に、比誘電率が2.5以下のものである。下限値に格別な制約は無いが、比誘電率は1より大きいものである。更に、厚さが10〜1000nmのものが好ましい。特に、厚さが30nm以上、200nm以下のものが好ましい。   In particular, the film A has a relative dielectric constant of 3 or less. In particular, the relative dielectric constant is 2.5 or less. Although there is no particular restriction on the lower limit value, the relative dielectric constant is larger than 1. Furthermore, the thing whose thickness is 10-1000 nm is preferable. In particular, a thickness of 30 nm or more and 200 nm or less is preferable.

そして、膜Aと膜Bとの複合膜は、その厚さが0.1〜1μm程度であることが好ましい。中でも、200nm以上、500nm以下のものが好ましい。   The composite film of film A and film B preferably has a thickness of about 0.1 to 1 μm. Especially, the thing of 200 nm or more and 500 nm or less is preferable.

本発明によればLow−k薄膜の弾性率が正確に得られる。特に、配線間絶縁膜としてのLow−k膜の剥離性や損傷度の評価基準となる弾性率が正確に求められる。   According to the present invention, the elastic modulus of the low-k thin film can be obtained accurately. In particular, an elastic modulus that is an evaluation standard for the peelability and damage degree of the Low-k film as the inter-wiring insulating film is accurately obtained.

すなわち、半導体デバイスにおける配線間絶縁膜の材料開発において非常に役立つ情報が簡便に得られ、特に、CMP工程やワイヤーボンディング工程における不良品の発生率(膜の剥離や損傷)に関する定量的な情報が得られる。   In other words, information that is very useful in the development of materials for inter-wiring insulating films in semiconductor devices can be easily obtained. In particular, quantitative information on the incidence of defective products (film peeling and damage) in the CMP process and wire bonding process can be obtained. can get.

本発明になる膜(半導体デバイスにおける配線間絶縁膜)特性(弾性率)測定方法は、膜(10〜1000nm厚の配線間絶縁膜)Aの特性を測定する方法である。そして、膜Aの上に設けられた該膜Aより高硬度な膜(例えば、キャップ膜)Bの上から膜強度(弾性率)を測定する方法である。特に、膜(配線間絶縁膜)Aよりも高硬度な膜(例えば、キャップ膜)Bを該膜Aの上に設けて複合膜を形成する成膜工程と、前記成膜工程の後、前記膜B上から該複合膜の特性を測定する測定工程とを具備する。更には、膜(配線間絶縁膜)Aよりも高硬度な膜(例えば、キャップ膜)Bを該膜Aの上に設けて複合膜を形成する成膜工程、及び前記成膜工程の後で前記膜B上から該複合膜の特性を測定する測定工程を具備し、前記膜Bの厚さが幾つかの場合において同様に行って膜Bの厚さが0の場合における膜Aの特性を算出する方法である。膜特性測定方法は、特に、圧子が膜に押込まれることで測定が行われる方法である。更には、圧子が膜に10nm〜200nmの深さ押込まれることで測定が行われる方法である。中でも、ナノインデンテーション法によって測定が行われる方法である。膜Aの上に積層される膜Bは、膜Aの硬度よりも高硬度なものであれば良いが、特に、弾性率が10GPa以上のものである。中でも、20GPa以上のものである。上限値に格別な制約は無いが、現実的には、70GPa程度のものである。積層する膜Bの厚さは、積層した複合膜の厚さが0.1〜1μm程度となるものである。中でも、30nm以上、500nm以下である。   The film (inter-wiring insulating film in a semiconductor device) characteristic (elastic modulus) measuring method according to the present invention is a method for measuring the characteristics of a film (inter-wiring insulating film having a thickness of 10 to 1000 nm) A. The film strength (elastic modulus) is measured from above a film (for example, a cap film) B having a higher hardness than the film A provided on the film A. In particular, a film forming step in which a film (for example, a cap film) B having a higher hardness than the film (inter-wiring insulating film) A is provided on the film A to form a composite film, and after the film forming step, A measurement step of measuring the characteristics of the composite membrane from above the membrane B. Further, a film forming step of forming a composite film by providing a film (for example, a cap film) B having a higher hardness than the film (inter-wiring insulating film) A on the film A, and after the film forming step A measurement step of measuring the characteristics of the composite film from above the film B, and the same process is performed in the case where the thickness of the film B is several, and the characteristics of the film A when the thickness of the film B is 0 This is a calculation method. The film characteristic measurement method is a method in which measurement is performed particularly when an indenter is pushed into the film. Furthermore, the measurement is performed by pressing the indenter into the film to a depth of 10 nm to 200 nm. Among them, the measurement is performed by the nanoindentation method. The film B laminated on the film A may be one having a hardness higher than that of the film A, but particularly has an elastic modulus of 10 GPa or more. Among them, it is 20 GPa or more. Although there is no particular restriction on the upper limit value, it is practically about 70 GPa. The thickness of the laminated film B is such that the laminated composite film has a thickness of about 0.1 to 1 μm. Especially, it is 30 nm or more and 500 nm or less.

本発明になる測定用試料は、膜(10〜1000nm厚の配線間絶縁膜)Aの特性(弾性率)を測定する為に用いられる測定用試料である。特に、上記の膜特性測定方法に用いられる測定用試料である。そして、膜Aの上に該膜Aより高硬度な膜Bが設けられたものである。膜Bは上記特徴の膜である。   The measurement sample according to the present invention is a measurement sample used for measuring the characteristics (elastic modulus) of the film (inter-wiring insulating film having a thickness of 10 to 1000 nm) A. In particular, it is a measurement sample used in the above-described method for measuring film characteristics. A film B having a higher hardness than the film A is provided on the film A. The film B is a film having the above characteristics.

以下、更に詳しく説明する。
図1は、本発明で用いられるナノインデンテーション法の概略図である。
This will be described in more detail below.
FIG. 1 is a schematic view of the nanoindentation method used in the present invention.

用いられる測定サンプルとして、Si基板上に所定の膜、即ち、Low−k膜が、その上にキャップ膜が積層されたものが用いられる。特に、CMP工程やワイヤーボンディング工程を経て得られる半導体素子と同様な構造を持つものが測定サンプルとして用意される。これは、実際の半導体素子の製造に出来るだけ近い形態で行なわれる方がより正確な情報が得られるであろうと言う観点からのものである。従って、試験(測定:評価)しようとするLow−k膜上のキャップ膜については、半導体素子に採用されるキャップ膜が使用される。Low−k膜上に積層されるキャップ膜としては、例えばSiO膜が挙げられる。尚、SiO膜の他にも、例えばSiC膜、SiN膜、SiCN膜、SiON膜、SiOC膜などを用いることが出来る。又、対象であるLow−k膜の厚さは、配線間絶縁膜としての厚さであることが好ましい。更に、膜の形成前後に実施する処理も、実際にCMPやワイヤーボンディングを行う場合のものと同様に行われていることが好ましい。このような処理の例としては、例えばプラズマ処理、密着助剤の使用、逆スパッタによる膜表面の粗面化などが挙げられる。   As a measurement sample to be used, a predetermined film, that is, a low-k film on a Si substrate and a cap film stacked thereon are used. In particular, a sample having a structure similar to that of a semiconductor element obtained through a CMP process or a wire bonding process is prepared as a measurement sample. This is from the viewpoint that more accurate information can be obtained if it is performed in a form as close as possible to the actual manufacturing of a semiconductor device. Therefore, as the cap film on the low-k film to be tested (measured: evaluated), the cap film employed in the semiconductor element is used. An example of the cap film stacked on the low-k film is a SiO film. In addition to the SiO film, for example, a SiC film, a SiN film, a SiCN film, a SiON film, a SiOC film, or the like can be used. In addition, the thickness of the target Low-k film is preferably a thickness as an inter-wiring insulating film. Furthermore, it is preferable that the processes performed before and after the film formation are performed in the same manner as in the case of actually performing CMP or wire bonding. Examples of such treatment include plasma treatment, use of an adhesion aid, and roughening of the film surface by reverse sputtering.

図2は、インデンテーションを行った際の弾性率を示すグラフである。
図1に示される通り、測定サンプルが圧子にて押し込まれる。インデンテーションの測定端子には、微小な振動が与えられており、その測定端子が測定サンプルの表面に達して測定が開始される。従来であれば、Si基板上には測定対象であるLow−k膜しか無い。この為、スタート時点がはっきりしないので、測定にバラツキが大きくなる傾向が有った。更には、得られた曲線のどの部分を計測値として採用すべきかが定かでは無かった。図2においても、比較的押込量の少ない領域では、圧子が十分入った領域で、測定値が横向きになる領域が有るものの、これらを定量的に定めるのは容易ではない。
FIG. 2 is a graph showing the elastic modulus when indentation is performed.
As shown in FIG. 1, the measurement sample is pushed with an indenter. A minute vibration is applied to the measurement terminal of the indentation, and the measurement terminal reaches the surface of the measurement sample to start measurement. Conventionally, there is only a Low-k film to be measured on the Si substrate. For this reason, since the starting point was not clear, there was a tendency for the measurement to vary greatly. Furthermore, it is not certain which part of the obtained curve should be adopted as the measurement value. Also in FIG. 2, in the region where the amount of pushing is relatively small, there is a region where the indenter is sufficiently inserted and the measured value is in the horizontal direction, but it is not easy to quantitatively determine these.

そこで、図3に示される如く、Si基板上に設けられた150nm厚のLow−k膜(絶縁膜)上にSiOからなるキャップ(Cap)膜がCVDにより積層された場合において、ナノインデンテーション法を用いて弾性率を測定(MTS社製のナノインデンターDCM−SA2を用いて測定)したので、その結果を図4に示す。すなわち、図4に示される如く、押込初期には、その値がどんどん下がって来る。それは、初期の値はCap膜の値であり、Cap膜が破られて下層の測定対象であるLow−k膜に達すると、その機械的強度の影響が出てきて下がると推測される。更に端子が押し込まれると、値は上昇し、結局、最小値を有する二次曲線のカーブが得られる。この最小値が複合膜の弾性率である。尚、最小値は曲線を微分することで容易に得られる。   Therefore, as shown in FIG. 3, when a cap film made of SiO is laminated by CVD on a 150-nm-thick low-k film (insulating film) provided on a Si substrate, a nanoindentation method is used. Was used to measure the elastic modulus (measured using Nanoindenter DCM-SA2 manufactured by MTS), and the results are shown in FIG. That is, as shown in FIG. 4, the value gradually decreases at the beginning of pressing. It is presumed that the initial value is the value of the Cap film, and when the Cap film is broken and reaches the Low-k film, which is a measurement target in the lower layer, the influence of the mechanical strength comes out and falls. As the terminal is further pushed in, the value rises and eventually a quadratic curve with a minimum value is obtained. This minimum value is the elastic modulus of the composite film. The minimum value can be easily obtained by differentiating the curve.

そして、Cap膜の厚みを変えた測定サンプルを用意し、同様な測定を行った。   And the measurement sample which changed the thickness of the Cap film | membrane was prepared, and the same measurement was performed.

このようにして得られた複合膜の弾性率とCap膜の厚さとの関係を図示したのが図5である。この図5において、Cap膜の厚さが0の位置に外挿すれば、Cap膜が無い場合での弾性率、即ち、所定厚のLow−k膜の弾性率が得られる。   FIG. 5 shows the relationship between the elastic modulus of the composite film thus obtained and the thickness of the Cap film. In FIG. 5, if the thickness of the Cap film is extrapolated to a position of 0, the elastic modulus without the Cap film, that is, the elastic modulus of the Low-k film having a predetermined thickness can be obtained.

そして、本手法により求めたバルクなLow−k膜の弾性率と他の手法で求められた弾性率とを比べた場合、同等なものであった。従って、本手法により得られた値は正しいものであることが判る。
尚、Low−k膜が二層以上の場合でも同様である。
And when the elasticity modulus of the bulk Low-k film calculated | required by this method and the elasticity modulus calculated | required by the other method were compared, it was equivalent. Therefore, it can be seen that the value obtained by this method is correct.
The same applies when the low-k film has two or more layers.

次に、上記の如きの積層(Low−k膜+Cap膜)構造の測定サンプルを四種類用意した。尚、サンプルAにおけるLow−k材の比誘電率は3.0、サンプルBにおけるLow−k材の比誘電率は2.4、サンプルCにおけるLow−k材の比誘電率は2.3、サンプルDにおけるLow−k材の比誘電率は2.3であった。そして、上記と同様にして複合弾性率を測定した。又、各サンプルについて、ワイヤーボンディングにおける引張試験を行った。このようにして得られた結果を基にして、複合弾性率と引張試験の結果(破壊強度)との関係を図6に示す。これによれば、両者の相関性が高いことが判る。すなわち、複合弾性率が高い値のサンプルA,Bではワイヤーボンディングの引っ張り試験でも強い値を示したのに対して、複合弾性率が低いサンプルC,Dはワイヤーボンディングの引っ張り試験でも低い値を示している。   Next, four types of measurement samples having the above-described laminated structure (Low-k film + Cap film) were prepared. The relative dielectric constant of the low-k material in sample A is 3.0, the relative dielectric constant of the low-k material in sample B is 2.4, and the relative dielectric constant of the low-k material in sample C is 2.3. The relative dielectric constant of the Low-k material in Sample D was 2.3. And the composite elastic modulus was measured like the above. Each sample was subjected to a tensile test in wire bonding. Based on the results thus obtained, FIG. 6 shows the relationship between the composite elastic modulus and the tensile test results (breaking strength). This shows that the correlation between the two is high. That is, samples A and B with high composite elastic modulus showed strong values in the wire bonding tensile test, while samples C and D with low composite elastic modulus showed low values in the wire bonding tensile test. ing.

ナノインデンテーション法の概略図Schematic diagram of nanoindentation method 弾性率−押込深さのグラフElastic modulus-indentation depth graph 本発明の膜特性測定用試料の概略図Schematic diagram of the sample for measuring membrane properties of the present invention 本発明になる複合弾性率−押込深さのグラフGraph of composite elastic modulus-indentation depth according to the present invention 複合弾性率−キャップ膜の膜厚のグラフComposite elastic modulus-Cap film thickness graph ワイヤーボンディング試験−複合弾性率のグラフ 代 理 人 宇 高 克 己Wire Bonding Test-Composite Elastic Modulus Graph Katsumi Utaka

Claims (12)

膜Aの特性を測定する方法であって、
膜Aの上に設けられた該膜Aより高硬度な膜Bの上から膜強度を測定する
ことを特徴とする膜特性測定方法。
A method for measuring the characteristics of membrane A, comprising:
A method for measuring film properties, comprising measuring film strength from a film B having a higher hardness than the film A provided on the film A.
膜Aの特性を測定する方法であって、
膜Aよりも高硬度な膜Bを該膜Aの上に設けて複合膜を形成する成膜工程と、
前記成膜工程の後、前記膜B上から該複合膜の特性を測定する測定工程
とを具備することを特徴とする膜特性測定方法。
A method for measuring the characteristics of membrane A, comprising:
A film forming step in which a film B having a hardness higher than that of the film A is provided on the film A to form a composite film;
A film characteristic measuring method comprising: measuring a characteristic of the composite film from above the film B after the film forming process.
膜Aの特性を測定する方法であって、
膜Aよりも高硬度な膜Bを該膜Aの上に設けて複合膜を形成する成膜工程、及び前記成膜工程の後で前記膜B上から該複合膜の特性を測定する測定工程を具備し、
前記膜Bの厚さが幾つかの場合において同様に行って膜Bの厚さが0の場合における膜Aの特性を算出することを特徴とする膜特性測定方法。
A method for measuring the characteristics of membrane A, comprising:
A film forming step for forming a composite film by providing a film B having a higher hardness than the film A on the film A, and a measuring step for measuring the characteristics of the composite film from the film B after the film forming step. Comprising
The film characteristic measurement method is characterized in that the characteristic of the film A when the thickness of the film B is 0 is calculated in the same manner when the thickness of the film B is several.
圧子が膜に押込まれることで測定が行われることを特徴とする請求項1〜請求項3いずれかの膜特性測定方法。   4. The film characteristic measuring method according to claim 1, wherein the measurement is performed by pressing the indenter into the film. 圧子が膜に10nm〜200nmの深さ押込まれることで測定が行われることを特徴とする請求項1〜請求項4いずれかの膜特性測定方法。   5. The film property measuring method according to claim 1, wherein the indenter is pressed into the film to a depth of 10 nm to 200 nm. ナノインデンテーション法によって測定が行われることを特徴とする請求項1〜請求項5いずれかの膜特性測定方法。   6. The film property measuring method according to claim 1, wherein the measurement is performed by a nanoindentation method. 膜Bは弾性率が10GPa以上のものであることを特徴とする請求項1〜請求項6いずれかの膜特性測定方法。   The film characteristic measuring method according to claim 1, wherein the film B has an elastic modulus of 10 GPa or more. 膜Aは比誘電率が3以下のものであることを特徴とする請求項1〜請求項7いずれかの膜特性測定方法。   The film characteristic measuring method according to claim 1, wherein the film A has a relative dielectric constant of 3 or less. 膜Aと膜Bとの和が0.1〜1μmであることを特徴とする請求項1〜請求項8いずれかの膜特性測定方法。   9. The film characteristic measuring method according to claim 1, wherein the sum of the film A and the film B is 0.1 to 1 [mu] m. 膜の弾性率を測定する方法であることを特徴とする請求項1〜請求項9いずれかの膜特性測定方法。   The method for measuring film characteristics according to any one of claims 1 to 9, which is a method for measuring an elastic modulus of a film. 膜Aの特性を測定する為に用いられる測定用試料であって、
膜Aの上に該膜Aより高硬度な膜Bが設けられたものである
ことを特徴とする膜特性測定用試料。
A measurement sample used for measuring the characteristics of the film A,
A film characteristic measurement sample, wherein a film B having a higher hardness than the film A is provided on the film A.
請求項1〜請求項10いずれかの膜特性測定方法に用いられる測定用試料であって、
膜Aの上に該膜Aより高硬度な膜Bが設けられたものである
ことを特徴とする膜特性測定用試料。
A measurement sample used in the film property measurement method according to any one of claims 1 to 10,
A film characteristic measurement sample, wherein a film B having a higher hardness than the film A is provided on the film A.
JP2005370649A 2005-12-22 2005-12-22 Method for measuring film characteristic and sample for film characteristic measurement Pending JP2007173610A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101933352B1 (en) 2018-06-22 2018-12-27 성균관대학교산학협력단 Measuring method for mechanical properties of coating layer

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101933352B1 (en) 2018-06-22 2018-12-27 성균관대학교산학협력단 Measuring method for mechanical properties of coating layer

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