WO2011132867A2 - Sputter target having stepped structure and sputtering device using same - Google Patents

Sputter target having stepped structure and sputtering device using same Download PDF

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Publication number
WO2011132867A2
WO2011132867A2 PCT/KR2011/002380 KR2011002380W WO2011132867A2 WO 2011132867 A2 WO2011132867 A2 WO 2011132867A2 KR 2011002380 W KR2011002380 W KR 2011002380W WO 2011132867 A2 WO2011132867 A2 WO 2011132867A2
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WIPO (PCT)
Prior art keywords
sputter target
target
stepped structure
recesses
present
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PCT/KR2011/002380
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French (fr)
Korean (ko)
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WO2011132867A3 (en
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박영춘
김진택
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Park Young-Chun
Kim Jin-Taek
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Publication of WO2011132867A2 publication Critical patent/WO2011132867A2/en
Publication of WO2011132867A3 publication Critical patent/WO2011132867A3/en

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/04—Coating on selected surface areas, e.g. using masks
    • C23C14/046—Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • C23C14/35—Sputtering by application of a magnetic field, e.g. magnetron sputtering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering
    • H01J37/3411—Constructional aspects of the reactor
    • H01J37/3414—Targets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02631—Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/20—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy

Definitions

  • the present invention relates to a stuffer target including a stepped structure used in the sputtering apparatus and a sputtering apparatus comprising the same.
  • the present invention relates to the surface structure of a target for sputtering. More specifically, the present invention relates to a technique for forming a more uniform thin film having good step coverage on a high step difference substrate structure by forming a stepped structure in a repeated or complex shape on the surface of the sputtering target.
  • Sputtering devices are used in various manufacturing devices, such as semiconductor devices such as various memories and logic, and hard disks, and the annual step ratio of each device wiring and connection is increasing due to the increase in the degree of integration of electronic devices.
  • FIG. 1 is a view showing the configuration and principle of a general DC magnetron sputtering device, generally referred to as a sputtering device to generate a plasma inside the device, and to collide the generated plasma with the surface of the target,
  • the material constituting the surface of the target (constituent material of the target) is protruded as particles, and the device that contacts the substrate to be processed to perform the treatment (for example, vapor deposition) of the surface of the substrate.
  • the sticking coefficient is almost 100%, so that a substrate having a high step cannot form a thin film with a uniform thickness.
  • the step coverage may be worse when the incident angle of the sputtering particles is a relatively asymmetrical incident beam.
  • sputtered particles are sputtered with a distribution of (cos ⁇ ) n (where n is 0.5-2 but usually close to 1 in the case of a sputter), so that the largest amount comes out in the vertical direction of the target and the further away from the vertical angle ( cos ⁇ ) decreases in proportion to n .
  • vertical beams are usually sent.
  • a limiter with holes punched in the direction perpendicular to the substrate is installed between the target and the substrate to compensate for the disadvantage of the general sputter by passing only the particles close to the vertical. Particles peel off from the limiter, rather causing particles, increasing the defective rate.
  • re-sputtering the substrate by re-depositing the deposition material on the floor to the side wall there is also a method to increase the deposition uniformity of the side wall near the floor to increase the deposition uniformity.
  • Korean Patent No. 10-0531991 proposes a sputtering apparatus having a vacuum chamber, a substrate holder, and a composite sputtering cathode provided with a shield between a plurality of targets.
  • a sputtering device proposed in the patent in more detail, a plurality of targets are used, and each target is provided with a shield.
  • the sputtering apparatus proposed in the above patent allows the limiter to adjust the straightness of the beam by bringing a limiter placed between the target and the substrate to the target and configuring the sputter target in the limiter.
  • the shield acting as a limiter must be electrically isolated from the sputter target.
  • the sputtering apparatus having the above structure has a problem that a plurality of targets must be used, and the structure is considerably complicated by separately providing shields serving as limiters on the plurality of targets.
  • an object of the present invention to provide a sputtering apparatus and a sputter target used therein, which have a simple structure and can adjust the direction of the sputtered beam.
  • an object of the present invention is to adjust the direction of the sputtered beam, that is, the angle of incidence range, using a step formed on the target surface.
  • Another object of the present invention is to adjust the straightness of the sputtered particles by the target itself by processing such that the target itself is powered to have a stepped structure, without installing a limiter installed to improve the straightness of the sputtered particles. It is to provide a stuffing device.
  • the sputter target according to an embodiment of the present invention is a sputter target used in a sputtering apparatus including a plasma discharge space, and has a constant depth (H) and width (L) inward from a surface of the sputter target facing the plasma discharge space.
  • a plurality of recesses formed to have and be surrounded by sidewalls; And a stepped structure in which the plurality of recesses are regularly arranged.
  • the stepped structure includes a recess group consisting of a plurality of recesses having the same depth and width, and regularly combining two or more recess groups having different widths (L) or step ratios (H / L) from each other. Arranged and formed.
  • the width of the plurality of recesses is formed to be larger than the thickness of the plasma sheath.
  • a sputtering apparatus includes: a plurality of recesses formed to have a constant depth H and width L inward from a surface of a sputter target facing the plasma discharge space and surrounded by sidewalls; And a sputter target including a stepped structure in which the plurality of recesses are regularly arranged.
  • a sputtering apparatus includes a plasma discharge space, a sputter target, and a means for guiding the plasma generated in the plasma discharge space to the sputter target, wherein the sputter target is the sputter on which the plasma is induced
  • the width of the plurality of recesses is formed to be larger than the thickness of the plasma sheath.
  • the sputter target having the stepped structure according to the present invention increases the straightness of the sputtered particle beam as the stepped ratio of the target surface structure increases, thereby minimizing the overhang of the hole inlet without reducing the thin film formation rate even in a high stepped ultrafine pattern. It is possible to form an optimal sputter beam capable of forming a more uniform thin film.
  • the sputter target having the above-described structure minimizes the disadvantages of the reduction of thin film formation rate and particle generation, such as a limiter, because the target itself controls the direction of the beam.
  • a sputter target having a stepped structure and a sputtering apparatus including the same according to the present invention are provided in the sputtering apparatus disclosed in Korean Patent Registration No.
  • the structure is not only simplified, but the practicality is significantly improved. It provides a beam source and apparatus ideal for the deposition of high step structures required by the process. Furthermore, the sputter target of the stepped structure of the present invention and the sputtering apparatus including the same have a higher step as the surface degree of the target for particle beam conversion having a larger incident angle as the deposition structure of the substrate has a higher step. By having a high step, the sputtered particle beam can be well deposited in the inside of a fine high step structure such as a semiconductor. In addition, the deposition property can be adjusted to be filled from the bottom of the high step structure with a high straightness.
  • FIG. 1 is a view showing the configuration and principle of a general DC magnetron sputtering device.
  • FIG. 2 is a view illustrating a deposition pattern of the sputtering apparatus shown in FIG. 1.
  • FIG 3 is a view showing the structure of a sputter target according to an embodiment of the present invention.
  • FIG. 4 is a view showing another embodiment of the step structure of the sputter target according to the present invention.
  • FIG. 5 is a view showing a step structure of the sputter target according to another embodiment of the present invention.
  • FIG. 6 is a SEM photograph showing a cross section of a copper thin film deposited under the same conditions using a general sputter target 6b and the sputter target 6a of the present invention.
  • FIG. 7 is an enlarged SEM photograph of a portion of FIG. 6.
  • FIG. 10 is a TEM cross-sectional view showing a TaN barrier deposited by the prior art.
  • 11 is a graph showing a comparison of the deposition thickness with respect to the incident angle in the present invention and the prior art.
  • 12 is a graph showing a comparison of deposition thickness against sidewall locations in the present invention and in the prior art.
  • the plasma generated inside the apparatus collides with the surface of the target, and the material constituting the surface of the target is thrown out as particles by the collision force, and the constituent material of the target emitted as the particles is to be processed.
  • the treatment of the substrate surface eg, deposition
  • the present invention relates to the surface structure of a sputter target for use in a sputtering apparatus including a plasma discharge space, and according to the present invention, a constant depth (H) and width (inward) from the surface of the sputter target facing the plasma discharge space (A plurality of recesses formed to have L) and surrounded by sidewalls; And a stepped structure in which the plurality of recesses are arranged regularly.
  • the cross section of the concave portion may be embodied in various ways such as square, circle, pentagon, hexagon.
  • the sputtered particle beam is formed on the surface of the sputter target by forming a stepped structure pattern having a step difference ratio necessary by etching or physical processing to adjust the angle of the sputtered particles on the surface of the sputter target.
  • FIG. 3 is a view showing the structure of a sputter target according to an embodiment of the present invention
  • Figure 3 (a) is a perspective view of the sputter target
  • Figure 3 (b) is a plan view
  • Figure 3 (c) is a view 3 ( It is sectional drawing of the said sputter target cut along the AA 'line
  • the sputter target 106 has a plurality of recesses formed on the surface of the sputter target itself.
  • the surface itself of the sputter target has a stepped structure having a plurality of recesses 106a and sidewalls 106b surrounding the recesses.
  • the stepped structure is formed in a regular pattern throughout the sputter target 106.
  • the stepped structure is formed in a pattern having a desired stepped ratio on the entire surface of the sputter target facing the plasma. The step ratio and size of the structure can be adjusted according to the shape and step of the substrate structure to be processed.
  • the straightness of the sputtered particle beam increases.
  • the step ratio here is defined as the depth / width of the recess (H / L in FIG. 3).
  • the ratio of the bottom surface of the fine structure to the area of the protruding portion of the surface determines the ratio of the beam whose straightness is adjusted by the step and the beam [(cos ⁇ ) n beam] generally sputtered by the surface.
  • the width of the concave portion can be selected in various ranges, but it is advantageous to maintain the step ratio by selecting it to be easy to process and larger than the plasma sheath thickness. For example, it is preferable to form the width of the concave portion at least twice the thickness of the plasma sheath.
  • the regularly patterned stepped structure is possible through various methods such as pattern etching, laser etching, electrochemical etching, or drilling. If necessary, a step pattern is formed by forming a pattern using one target and then attaching it to another sputter target or depositing another material on a sputter target having a structure or a pattern that fits another target on a machined target. Various processing methods that can form the can be used. Different materials are possible when attaching or joining two or more targets.
  • the pattern may be selected according to the process structure and conditions since plasma ions may affect the formation efficiency of the sputtered particle beam and the reflected beam when the plasma ions are incident on the sputter target.
  • the pattern formed on the target may be simply mixed with one or more patterns according to the needs of the process, starting from one pattern, and the stepped ratio may be appropriately mixed with the same pattern or different patterns as required.
  • the cross section of the hole that is, the cross section of the groove 106a may be implemented in various shapes that can regularly fill a plane such as a square, a circle, a pentagon, a hexagon, a straight line, a rhombus, and the like.
  • . 4 is a view showing another embodiment of the step structure of the sputter target according to the present invention, illustrating a circle (Fig. 4 (a)), a hexagon (Fig. 4 (b)) and a straight (Fig. 4 (c)) .
  • FIG. 5 is a view showing a stepped structure of a sputter target according to another embodiment of the present invention
  • Figure 5 (a) is a perspective view of the sputter target
  • Figure 5 (b) is a plan view
  • Figure 5 (c) is A cross-sectional view of the sputter target cut along the line AA ′ of FIG. 5 (b).
  • a concave group consisting of a plurality of recesses having the same depth and width, and two or more concave groups having different widths (L) or step ratios (H / L) are regularly arranged in combination.
  • the sputter target 106 having a stepped structure including two or more concave groups can adjust the amount of each and the reflection angle range of the sputter target constituent particles emitted by the plasma ions.
  • a plurality of cylindrical holes having a 2 to 1 step are regularly arranged on the surface.
  • Each hole is 3mm in diameter and 6mm deep and the spacing between holes is 2mm, which causes the sputtered particles to control the angle of sputter beam in the hole to about 26.5 degrees or less by the angle created by the ratio of two to one. You can do it. Since the angle of the beam to be controlled varies according to the step difference ratio of the recess of the target, it is possible to form an appropriate step ratio suitable for the high step trench to be deposited.
  • ECR plasma source a high vacuum Lisitano-coil ECR plasma source was used.
  • One of the characteristics of ECR plasma is to form a high density plasma (10 10 ⁇ 10 12 cm -3 ) for high ionization rate, and also can operate at a pressure of 1 mTorr or less. They are arranged on the side of the plasma discharge space.
  • FIG. 6 is a SEM photograph showing a cross section of a copper thin film deposited under the same conditions using a general sputter target and the sputter target of the present invention
  • FIG. 7 is an enlarged SEM photograph of a portion of FIG. 6.
  • 6 and 7 (a) shows the experimental results of the conventional sputter target, (b) shows the experimental results of the sputter target having a stepped structure of the present invention, respectively. As shown in FIG. 6 and FIG.
  • the sputtered particles are sputtered with a distribution of (cos ⁇ ) n , so that the largest amount comes out in the vertical direction of the target and decreases in proportion to (cos ⁇ ) n as the distance from the vertical angle (n is 0.5-2; Generally n ⁇ 1).
  • the deposition thickness according to the incident angle of the normal sputter target and the sputter target according to the present invention were compared, and the results are shown in FIG. 8. 8, it can be seen how the difference in the distribution of the sputtered beam compared to the general cos ⁇ is expected using the copper deposition pattern used in the experiment.
  • the dotted line in blue represents the sin ⁇ curve corresponding to the integral value of the deposited thickness according to the angle when the beam descends to cos ⁇
  • the solid yellow line is the expected deposition curve when the beam descends within 26.5 degrees through the stepped target.
  • Indication of the thickness deposited at each trench point according to the open angle to the opening shows that both the general sputter target and the new sputter target of the present invention are relatively in good agreement with the expectation.
  • Checking the thickness according to the sidewall position of the deposition pattern (where wall position 0 indicated on the horizontal axis is the top end of the wall and 5 is the bottom end of the wall), as shown in FIG. As the sputter target was reduced in the amount of deposition on the upper end, it was confirmed that the thickness of the upper end and the lower end of the wall became more uniform.
  • FIG. 10 is a TEM cross-sectional view showing a TaN barrier deposited by the prior art, and a TEM cross-section (a) and Applied materials (AMAT) published in 2009 by Novellus, USA, shown in FIG. Comparing the TEM cross-section picture (b) published in 2011, as shown in Fig. 11, the sputtered beams of the two companies follow the distribution of cos ⁇ , and to correct wall deposition at a low incident angle or near the bottom of the stepped structure. Re-sputtering occurs due to bias applied to the substrate, and it is confirmed that the difference is as much as re-sputtering in the general sputtering curve.
  • the present invention in the case of a thin film deposited using a sputter target having a stepped structure according to the present invention in terms of thickness on a sidewall position, the present invention is formed by forming a uniform thickness of 50% or more than that of AMAT or Novellus. It is proven to be superior to the most advanced technology.

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Abstract

According to the present invention, a sputter target comprises: a plurality of concave parts formed to have constant depth (H) and width (L) inward from the surface of the sputter target, which faces a plasma discharge space, and to be surrounded by lateral walls; and a stepped structure constructed by regularly arranging the plurality of concave parts. According to the present invention, the sputter target having a stepped structure is configured such that the directionality of a sputtered particle beam is adjusted by the size of the stepped structure of a surface, which makes it possible to deposit a high-stepped structure required in a process. In addition, the sputtering device according to the present invention is processed such that the target itself supplied with power has a stepped structure, so that it is possible to adjust the linearity of a particle sputtered by the target itself, without a limiter provided to improve the linearity of sputtered particles.

Description

단차구조를 포함하는 스퍼터 타켓 및 이를 이용하는 스퍼터링 장치Sputter target including stepped structure and sputtering device using the same
본 발명은 스퍼터링 장치에 사용되는 단차구조를 포함하는 스터퍼 타겟 및 이를 포함하는 스퍼터링 장치에 관한 것이다. 구체적으로, 본 발명은 스퍼터링을 위한 타겟의 표면 구조에 관한 것이다. 보다 구체적으로는 본 발명을 스퍼터링 타겟 표면에 반복된 형태나 복합적 형태의 단차구조를 형성함으로써 고단차비 기판 구조물 위에 스텝 커버리지가 좋은 보다 균일한 박막을 형성하는 기술에 관한 것이다.The present invention relates to a stuffer target including a stepped structure used in the sputtering apparatus and a sputtering apparatus comprising the same. In particular, the present invention relates to the surface structure of a target for sputtering. More specifically, the present invention relates to a technique for forming a more uniform thin film having good step coverage on a high step difference substrate structure by forming a stepped structure in a repeated or complex shape on the surface of the sputtering target.
각종 메모리나 로직과 같은 반도체 디바이스를 비롯하여 하드디스크 등 다양한 제조에 스퍼터링 장치가 사용되고 있으며 해마다 전자기기 집적도의 증가로 인해 각 디바이스 배선 및 연결부의 단차비가 점점 커지고 있다.Sputtering devices are used in various manufacturing devices, such as semiconductor devices such as various memories and logic, and hard disks, and the annual step ratio of each device wiring and connection is increasing due to the increase in the degree of integration of electronic devices.
도 1은 일반적인 DC 마그네트론 스퍼터링 장치의 구성 및 원리를 보여주는 도면으로서, 일반적으로 스퍼터링 장치라 함은 상기 장치의 내부에 플라즈마를 생성하고, 생성된 플라즈마를 타겟의 표면과 충돌시키고, 충돌하는 힘에 의해 타겟의 표면을 구성하는 재료(타겟의 구성재료)가 입자로서 튀어 나오고, 상기 타겟의 구성재료가 처리하고자 하는 기판과 접촉하여 기판 표면의 처리(예를 들면, 증착)를 수행하는 장치를 말한다. 그러나, 스퍼터된 입자가 여러 방향으로부터 기판에 입사하고 기판에 도달하는 순간 접착율(Sticking coefficient)이 거의 100%에 가까워 고단차를 가진 기판의 경우 균일한 두께로 박막을 형성할 수 없다. 더불어 기판의 끝부분에서는 스퍼터링 입자의 입사각도가 상대적으로 좌우비대칭적인 입사빔일 경우 단차피복성이 더 좋지 못할 수 있는 단점이 있다.1 is a view showing the configuration and principle of a general DC magnetron sputtering device, generally referred to as a sputtering device to generate a plasma inside the device, and to collide the generated plasma with the surface of the target, The material constituting the surface of the target (constituent material of the target) is protruded as particles, and the device that contacts the substrate to be processed to perform the treatment (for example, vapor deposition) of the surface of the substrate. However, when the sputtered particles enter the substrate from various directions and reach the substrate, the sticking coefficient is almost 100%, so that a substrate having a high step cannot form a thin film with a uniform thickness. In addition, at the end of the substrate, the step coverage may be worse when the incident angle of the sputtering particles is a relatively asymmetrical incident beam.
이러한 특성으로 고단차의 초미세 패턴을 갖는 기판에 대한 박막을 형성할 때, 고단차 구조물 입구에 박막의 오버행이 생기게 되고, 아랫면으로 갈수록 벽면에 박막이 균일하게 형성될 수 없게 될 뿐만 아니라, 바닥 커버리지율도 저하된다는 문제점이 있다(도 2 참조).Due to this characteristic, when forming a thin film for a substrate having a high stepped ultra fine pattern, an overhang of the thin film is formed at the entrance of the high stepped structure, and the thin film cannot be uniformly formed on the wall toward the bottom, There is a problem that the coverage ratio is also lowered (see Fig. 2).
이를 개선하기 위해, 종래 기술에서도 스퍼터링을 행할 때의 진공도를 향상시킴으로써 스퍼터링 입자의 평균자유행로를 크게 하여 스퍼터링 입자의 직진성을 향상시키고 타겟과 기판의 거리를 크게 하여 수직입사성분을 크게 하고 있다. 일반적으로 스퍼터된 입자는 (cosθ)n (스퍼터의 경우 n은 0.5-2 이나 보통 1에 가까움)의 분포로 스퍼터되어 나오므로 타겟의 수직한 방향으로 가장 많은 양이 나오고 수직각에서 멀어질수록 (cosθ)n 에 비례하여 줄어들게 된다. 고단차 구조물을 바닥에서부터 채우고 오버행을 줄이기 위해서는 수직빔을 주로 보내 주어야 한다. 이를 위해 타겟과 기판 사이에 기판에 수직인 방향으로 구멍이 뚫려 있는 리미터를 설치하여 수직에 가까운 입자만을 통과시킴으로써 일반적인 스퍼터의 단점을 보완하고 있지만, 리미터에 쌓이는 입자들로 인한 박막 형성율의 감소와 리미터로부터입자가 박리하여 오히려 파티클 생성의 원인이 되어 불량율을 증가시킨다. 한편 기판의 리스퍼터링(re-sputtering)을 통해 바닥에 있는 증착물질을 옆벽면으로 재증착시킴으로 바닥에 가까운 옆 벽면의 증착율을 높여 증착 균일도를 높이는 방법도 있다.In order to improve this, in the prior art, by improving the degree of vacuum during sputtering, the average free path of the sputtered particles is increased to improve the straightness of the sputtered particles, and the distance between the target and the substrate is increased to increase the vertical incidence component. In general, sputtered particles are sputtered with a distribution of (cosθ) n (where n is 0.5-2 but usually close to 1 in the case of a sputter), so that the largest amount comes out in the vertical direction of the target and the further away from the vertical angle ( cos θ) decreases in proportion to n . In order to fill high-level structures from the bottom and to reduce overhangs, vertical beams are usually sent. To this end, a limiter with holes punched in the direction perpendicular to the substrate is installed between the target and the substrate to compensate for the disadvantage of the general sputter by passing only the particles close to the vertical. Particles peel off from the limiter, rather causing particles, increasing the defective rate. On the other hand, by re-sputtering the substrate by re-depositing the deposition material on the floor to the side wall, there is also a method to increase the deposition uniformity of the side wall near the floor to increase the deposition uniformity.
리미터의 변형예로서, 한국등록특허 10-0531991은 진공조와, 기판홀더와, 복수의 타겟 간에 차폐물이 설치된 복합 스퍼터링 캐소드를 갖는 스퍼터링장치를 제안하고 있다. 상기 특허에서 제안한 스퍼터링 장치를 보다 자세히 살펴보면, 복수의 타겟이 사용되고 있으며, 각각의 타겟에는 차폐물이 설치된다. 상기 특허에서 제안된 스퍼터링 장치는, 일반적으로 타겟과 기판사이에 놓이는 리미터를 타겟에 가져와 스퍼터 타겟을 리미터 안에 구성하는 형태를 통해 리미터가 빔의 직진성을 조절할 수 있도록 한 것이다. 이 경우 리미터로 작용하는 차폐물은 스퍼터 타겟과 전기적으로 절연이 되어야 한다. 더 나아가 상기한 구조를 갖는 스퍼터링 장치는, 복수의 타겟을 사용해야 하고, 각각의 복수의 타겟에 리미터로서 작용하는 차폐물을 별도로 설치함으로써 구조가 상당히 복잡해진다는 문제점을 안고 있다.As a modification of the limiter, Korean Patent No. 10-0531991 proposes a sputtering apparatus having a vacuum chamber, a substrate holder, and a composite sputtering cathode provided with a shield between a plurality of targets. Looking at the sputtering device proposed in the patent in more detail, a plurality of targets are used, and each target is provided with a shield. The sputtering apparatus proposed in the above patent allows the limiter to adjust the straightness of the beam by bringing a limiter placed between the target and the substrate to the target and configuring the sputter target in the limiter. In this case, the shield acting as a limiter must be electrically isolated from the sputter target. Furthermore, the sputtering apparatus having the above structure has a problem that a plurality of targets must be used, and the structure is considerably complicated by separately providing shields serving as limiters on the plurality of targets.
상기 종래기술의 단점을 보완하기 위해, 본 발명의 목적은 단순한 구조를 갖고 있으면서도 스퍼터된 빔의 방향성을 조절할 수 있는 스퍼터링 장치 및 이에 사용되는 스퍼터 타겟을 제공하는 것이다. 구체적으로, 본 발명은 타겟 표면에 형성된 단차를 이용하여 스퍼터된 빔의 방향성 즉, 입사각도 범위를 조절하는 것을 목적으로 한다.In order to supplement the disadvantages of the prior art, it is an object of the present invention to provide a sputtering apparatus and a sputter target used therein, which have a simple structure and can adjust the direction of the sputtered beam. Specifically, an object of the present invention is to adjust the direction of the sputtered beam, that is, the angle of incidence range, using a step formed on the target surface.
본 발명의 다른 목적은, 스퍼터된 입자의 직진성을 향상시키기 위해 설치되는 리미터를 설치하지 않고도, 전원이 공급되는 타겟 자체가 단차구조를 갖도록 가공함으로 타겟 자체에 의해 스퍼터된 입자의 직진성을 조절할 수 있다는 스터퍼링 장치를 제공하는 것이다.Another object of the present invention is to adjust the straightness of the sputtered particles by the target itself by processing such that the target itself is powered to have a stepped structure, without installing a limiter installed to improve the straightness of the sputtered particles. It is to provide a stuffing device.
본 발명의 일 예에 따른 스퍼터 타겟은 플라즈마 방전 공간을 포함하는 스퍼터링 장치에 사용되는 스퍼터 타겟으로서, 상기 플라즈마 방전 공간에 대향하는 스퍼트 타겟의 표면으로부터 내측으로 일정한 깊이(H)와 너비(L)를 갖도록 형성되어 측벽에 의해서 둘러싸이는 복수의 오목부; 및 상기 복수의 오목부가 규칙적으로 배열되어 구성되는 단차구조를 포함한다.The sputter target according to an embodiment of the present invention is a sputter target used in a sputtering apparatus including a plasma discharge space, and has a constant depth (H) and width (L) inward from a surface of the sputter target facing the plasma discharge space. A plurality of recesses formed to have and be surrounded by sidewalls; And a stepped structure in which the plurality of recesses are regularly arranged.
상기 단차구조는 동일한 깊이와 너비를 갖는 복수의 오복부들로 구성되는 오목부 그룹을 포함하고, 서로 상이한 너비(L) 또는 단차비(H/L)를 갖는 두 개 이상의 오목부 그룹들이 규칙적으로 조합 배열되어 형성된다. The stepped structure includes a recess group consisting of a plurality of recesses having the same depth and width, and regularly combining two or more recess groups having different widths (L) or step ratios (H / L) from each other. Arranged and formed.
상기 복수의 오목부의 너비는 플라즈마 쉬쓰(plasma sheath) 두께 보다는 크게 형성된다. The width of the plurality of recesses is formed to be larger than the thickness of the plasma sheath.
본 발명의 다른 예에 따른 스퍼터링 장치는 플라즈마 방전 공간에 대향하는 스퍼트 타겟의 표면으로부터 내측으로 일정한 깊이(H)와 너비(L)를 갖도록 형성되어 측벽에 의해서 둘러싸이는 복수의 오목부; 및 상기 복수의 오목부가 규칙적으로 배열되어 구성되는 단차구조를 포함하는 스퍼터 타겟을 포함한다.According to another embodiment of the present invention, a sputtering apparatus includes: a plurality of recesses formed to have a constant depth H and width L inward from a surface of a sputter target facing the plasma discharge space and surrounded by sidewalls; And a sputter target including a stepped structure in which the plurality of recesses are regularly arranged.
본 발명의 또 다른 예에 따른 스퍼터링 장치는 플라즈마 방전 공간, 스퍼터 타겟, 및 상기 플라즈마 방전공간에서 생성된 플라즈마를 상기 스퍼터 타겟으로 유도하는 수단을 포함하고, 상기 스퍼터 타겟이 상기 플라즈마가 유도되는 상기 스퍼터 타겟의 표면으로부터 내측으로 일정한 깊이(H)와 너비(L)를 갖도록 형성되어 측벽에 의해서 둘러싸이는 복수의 오목부; 및 상기 복수의 오목부가 규칙적으로 배열되어 구성되는 단차구조를 포함한다.A sputtering apparatus according to another embodiment of the present invention includes a plasma discharge space, a sputter target, and a means for guiding the plasma generated in the plasma discharge space to the sputter target, wherein the sputter target is the sputter on which the plasma is induced A plurality of recesses formed to have a constant depth H and a width L inward from the surface of the target and surrounded by the sidewalls; And a stepped structure in which the plurality of recesses are regularly arranged.
상기 복수의 오목부의 너비는 플라즈마 쉬쓰(plasma sheath) 두께 보다는 크게 형성된다.The width of the plurality of recesses is formed to be larger than the thickness of the plasma sheath.
본 발명에 따른 단차구조를 갖는 스퍼터 타겟은 타겟 표면 구조의 단차비가 커질수록 스퍼터된 입자빔의 직진성이 증가하기 때문에 고단차 초미세 패턴에서도 박막 형성율을 감소시키지 않고 홀 입구의 오버행을 최소화하고 벽멱에 보다 균일한 박막을 형성시킬 수 있는 최적의 스퍼터 빔을 형성할 수 있다. 또한 상기한 구조의 스퍼터 타겟은 타겟 자체가 빔의 방향성을 조절하므로 리미터와 같이박막 형성율의 감소나 파티클 생성의 단점을 극소화 하며 어떠한 스퍼터 장치에서도 타겟만으로 빔의 방향성을 조절할 수 있는 장점이 있다. 본 발명에 따른 단차구조의 스퍼터 타겟 및 이를 포함하는 스퍼터링 장치는 기존의 한국등록특허 제10-0531991호(복수의 타겟과 각각의 타겟에 리미터로 작용하는 차폐물을 설치한 구조)에 개시된 스퍼터링 장치에 비해 그 구조가 단순화될 뿐 아니라 실용성이 현저히 향상된다. 공정에서 필요로 하는 고단차 구조물 증착에 이상적인 빔 소스 및 장치를 제공한다. 더 나아가, 본 발명의 단차 구조의 스퍼터 타겟 및 이를 포함하는 스퍼터링 장치는 기판의 증착 구조물이 고단차를 가지면 가질수록 입사각이 큰 입자빔 변환을 위해 타겟의 표면도와 같은 정도의 고단차를 가지게 하거나 더 높은 단차를 가지게 함으로써 반도체와 같은 미세한 고단차 구조물의 내부에 스퍼터된 입자빔이 잘 증착되도록 할 수 있고, 더불어 직진성을 높여 고단차 구조물의 밑바닥에서부터 채워나가도록 증착 특성을 조절할 수 있다.The sputter target having the stepped structure according to the present invention increases the straightness of the sputtered particle beam as the stepped ratio of the target surface structure increases, thereby minimizing the overhang of the hole inlet without reducing the thin film formation rate even in a high stepped ultrafine pattern. It is possible to form an optimal sputter beam capable of forming a more uniform thin film. In addition, the sputter target having the above-described structure minimizes the disadvantages of the reduction of thin film formation rate and particle generation, such as a limiter, because the target itself controls the direction of the beam. A sputter target having a stepped structure and a sputtering apparatus including the same according to the present invention are provided in the sputtering apparatus disclosed in Korean Patent Registration No. 10-0531991 (a structure in which a plurality of targets and shields acting as limiters are provided on each target). In comparison, the structure is not only simplified, but the practicality is significantly improved. It provides a beam source and apparatus ideal for the deposition of high step structures required by the process. Furthermore, the sputter target of the stepped structure of the present invention and the sputtering apparatus including the same have a higher step as the surface degree of the target for particle beam conversion having a larger incident angle as the deposition structure of the substrate has a higher step. By having a high step, the sputtered particle beam can be well deposited in the inside of a fine high step structure such as a semiconductor. In addition, the deposition property can be adjusted to be filled from the bottom of the high step structure with a high straightness.
도 1은 일반적인 DC 마그네트론 스퍼터링 장치의 구성 및 원리를 보여주는 도면이다.1 is a view showing the configuration and principle of a general DC magnetron sputtering device.
도 2는 도 1에 도시된 스퍼터링 장치의 증착패턴을 보여주는 도면이다. FIG. 2 is a view illustrating a deposition pattern of the sputtering apparatus shown in FIG. 1.
도 3은 본 발명의 실시예에 따른 스퍼터 타겟의 구조를 보여주는 도면이다. 3 is a view showing the structure of a sputter target according to an embodiment of the present invention.
도 4는 본 발명에 따른 스퍼터 타겟의 단차구조의 다른 실시예를 보여주는 도면이다. 4 is a view showing another embodiment of the step structure of the sputter target according to the present invention.
도 5는 본 발명의 또 다른 실시예에 따른 스퍼터 타겟의 단차구조를 보여주는 도면이다. 5 is a view showing a step structure of the sputter target according to another embodiment of the present invention.
도 6은 일반적인 스퍼터 타겟(6b)과 본 발명의 스퍼터 타겟 (6a)을 이용하여 동일 조건에서 증착한 구리 박막의 단면을 보여주는 SEM 사진이다. FIG. 6 is a SEM photograph showing a cross section of a copper thin film deposited under the same conditions using a general sputter target 6b and the sputter target 6a of the present invention.
도 7은 도 6의 일부를 확대한 SEM 사진이다. 7 is an enlarged SEM photograph of a portion of FIG. 6.
도 8은 입사각에 대한 증착 두께를 보여주는 그래프이다. 8 is a graph showing deposition thickness versus incident angle.
도 9는 벽면(sidewall) 위치에 대한 증착 두께를 보여주는 그래프이다. 9 is a graph showing deposition thickness versus sidewall location.
도 10은 종래기술에 의해 증착된 TaN 배리어를 보여주는 TEM 단면사진이다. 10 is a TEM cross-sectional view showing a TaN barrier deposited by the prior art.
도 11은 본 발명기술과 종래기술에서 입사각에 대한 증착 두께를 비교하여 보여주는 그래프이다.11 is a graph showing a comparison of the deposition thickness with respect to the incident angle in the present invention and the prior art.
도 12는 본 발명기술과 종래기술에서 벽면(sidewall) 위치에 대한 증착 두께를 비교하여 보여주는 그래프이다. 12 is a graph showing a comparison of deposition thickness against sidewall locations in the present invention and in the prior art.
스퍼터링 장치는 상기 장치의 내부에 생성된 플라즈마가 상기 타겟의 표면과 충돌하고, 충돌하는 힘에 의해 타겟의 표면을 구성하는 재료가 입자로서 튀어 나오고, 입자로서 방출된 타겟의 구성재료가 처리하고자 하는 기판과 접촉하여 기판 표면의 처리(예를 들면, 증착)를 수행하게 된다. 본 발명은 플라즈마 방전 공간을 포함하는 스퍼터링 장치에 사용되는 스퍼터 타겟의 표면구조에 관련된 것으로서, 본 발명에 따르면, 상기 플라즈마 방전 공간에 대향하는 스퍼터 타겟의 표면으로부터 내측으로 일정한 깊이(H)와 너비(L)를 갖도록 형성되어 측벽에 의해서 둘러싸이는 복수의 오목부; 및 상기 복수의 오목부가 규칙적으로 배열되어 구성되는 단차구조를 포함하는 스퍼터 타겟이 제공된다. 상기 오목부의 단면은 사각형, 원형,오각형, 육각형 등 다양하게 구현될 수 있다. 보다 구체적으로, 본 발명에 따르면, 스퍼터 타겟의 표면에서 스퍼터된 입자의 각도를 조절할 수 있도록 타겟 표면에 에칭, 또는 물리적 가공 등의 방법으로 필요한 단차비를 갖는 단차구조 패턴을 형성하여 스퍼터된 입자빔의 방향성과 빔각도 범위를 조절함으로 기판의 고단차 미세구조 증착에 적절한 스퍼터 타겟 및 이를 포함하는 스퍼터링 장치가 제공된다.In the sputtering apparatus, the plasma generated inside the apparatus collides with the surface of the target, and the material constituting the surface of the target is thrown out as particles by the collision force, and the constituent material of the target emitted as the particles is to be processed. In contact with the substrate, the treatment of the substrate surface (eg, deposition) is performed. The present invention relates to the surface structure of a sputter target for use in a sputtering apparatus including a plasma discharge space, and according to the present invention, a constant depth (H) and width (inward) from the surface of the sputter target facing the plasma discharge space ( A plurality of recesses formed to have L) and surrounded by sidewalls; And a stepped structure in which the plurality of recesses are arranged regularly. The cross section of the concave portion may be embodied in various ways such as square, circle, pentagon, hexagon. More specifically, according to the present invention, the sputtered particle beam is formed on the surface of the sputter target by forming a stepped structure pattern having a step difference ratio necessary by etching or physical processing to adjust the angle of the sputtered particles on the surface of the sputter target. By adjusting the directionality and the beam angle range of the present invention, a sputter target and a sputtering apparatus including the same are provided.
도 3은 본 발명의 실시예에 따른 스퍼터 타겟의 구조를 보여주는 도면으로서, 도 3(a)는 상기 스퍼터 타겟의 사시도이고, 도 3(b)는 평면도이고, 도 3(c)는 도 3(b)의 A-A' 선을 따라 절단한 상기 스퍼터 타겟의 절단 단면도이다.3 is a view showing the structure of a sputter target according to an embodiment of the present invention, Figure 3 (a) is a perspective view of the sputter target, Figure 3 (b) is a plan view, Figure 3 (c) is a view 3 ( It is sectional drawing of the said sputter target cut along the AA 'line | wire of b).
도 3에 도시된 바와 같이, 상기 스퍼터 타겟(106)은 복수의 오목부가 스퍼터 타겟 자체의 표면에 형성되어 있다. 이러한 복수의 오목부의 형성에 의해, 스퍼터 타겟의 표면 자체에는 복수의 오목부(106a)와 상기 오목부를 둘러싸는 측벽(106b)을 갖는 단차구조를 갖는다. 상기 단차구조는 스퍼터 타겟(106)의 전체에 걸쳐 규칙적으로 패턴되어 형성된다. 상기한 단차 구조는 스퍼터 타겟의 플라즈마를 향한 면 전체에 원하는 단차비를 가지는 패턴으로 형성된다. 구조물의 단차비와 크기는 공정처리를 원하는 기판 구조의 모양, 단차에 따라 조절할 수 있다. 스퍼터 타겟 표면구조의 단차비가 커질수록 스퍼터된 입자빔의 직진성이 증가한다. 여기서 단차비는 오목부의 깊이/너비(도 3에서 H/L)로 정의된다. 여기서 표면에 돌출된 부위의 면적 대비 파인 구조의 바닥 면의 비율은 단차에 의해 직진성이 조절된 빔과 표면에 의해 일반적으로 스퍼터된 빔 [(cosθ)n 빔]의 비율을 결정한다. 단차구조에서 오목부의 너비는 다양한 범위의 선택이 가능하나 가공이 용이하고 플라즈마 쉬쓰(plasma sheath) 두께 보다는 크도록 선택하는 것이 단차비를 유지하는데 유리하다. 예를 들어, 상기 오목부의 너비를 플라즈마 쉬쓰 두께의 2배 이상으로 형성하는 것이 바람직하다.As shown in FIG. 3, the sputter target 106 has a plurality of recesses formed on the surface of the sputter target itself. By forming such a plurality of recesses, the surface itself of the sputter target has a stepped structure having a plurality of recesses 106a and sidewalls 106b surrounding the recesses. The stepped structure is formed in a regular pattern throughout the sputter target 106. The stepped structure is formed in a pattern having a desired stepped ratio on the entire surface of the sputter target facing the plasma. The step ratio and size of the structure can be adjusted according to the shape and step of the substrate structure to be processed. As the step ratio of the sputter target surface structure increases, the straightness of the sputtered particle beam increases. The step ratio here is defined as the depth / width of the recess (H / L in FIG. 3). Here, the ratio of the bottom surface of the fine structure to the area of the protruding portion of the surface determines the ratio of the beam whose straightness is adjusted by the step and the beam [(cosθ) n beam] generally sputtered by the surface. In the stepped structure, the width of the concave portion can be selected in various ranges, but it is advantageous to maintain the step ratio by selecting it to be easy to process and larger than the plasma sheath thickness. For example, it is preferable to form the width of the concave portion at least twice the thickness of the plasma sheath.
상기 규칙적으로 패턴화된 단차구조는 패턴에칭, 레이저 에칭, 전기화학적 에칭, 또는 드릴링 등 여러 가지 방법을 통해 가능하다. 필요한 경우 한 개의 타겟을 사용하여 패턴을 형성한 후에 다른 스퍼터 타겟에 붙이거나 혹은 기 가공된 타겟에 다른 타겟을 끼우는 구조 혹은 패턴을 가진 스퍼터 타겟 위에 다른 물질을 증착하여 단차패턴을 형성하는 등 단차구조를 형성할 수 있는 다양한 가공방법을 사용할 수 있다. 두개 이상의 타겟을 붙이거나 결합할 때 서로 다른 물질도 가능하다. 패턴은 플라즈마 이온이 스퍼터 타겟에 입사할 때 스퍼터된 입자빔의 형성 효율 및 반사되어 나오는 빔에 영향을 미칠 수 있으므로 공정구조 및 조건에 따라 선택할 수 있다. 또한 타겟에 형성되는 패턴은 단순하게는 한가지 패턴에서 시작하여 공정의 필요에 따라 여러 패턴을 섞을 수도 있고, 단차비도 필요에 의해 여러 단차비의 같은 패턴, 혹은 다른 패턴을 적절히 섞어 사용할 수 있다.The regularly patterned stepped structure is possible through various methods such as pattern etching, laser etching, electrochemical etching, or drilling. If necessary, a step pattern is formed by forming a pattern using one target and then attaching it to another sputter target or depositing another material on a sputter target having a structure or a pattern that fits another target on a machined target. Various processing methods that can form the can be used. Different materials are possible when attaching or joining two or more targets. The pattern may be selected according to the process structure and conditions since plasma ions may affect the formation efficiency of the sputtered particle beam and the reflected beam when the plasma ions are incident on the sputter target. In addition, the pattern formed on the target may be simply mixed with one or more patterns according to the needs of the process, starting from one pattern, and the stepped ratio may be appropriately mixed with the same pattern or different patterns as required.
단차구조가 형성된 스퍼터 타겟에서, 상기 홀의 단면, 다시 말해 홈(106a)의 단면은 사각형, 원형, 오각형, 육각형, 직선형, 마름모형 등 평면을 규칙적으로 채울 수 있는 모든 형상이 다양하게 구현될 수 있다. 도 4는 본 발명에 따른 스퍼터 타겟의 단차구조의 다른 실시예를 보여주는 도면으로서, 원형(도 4(a)), 육각형(도 4(b)) 및 직선형(도 4(c))을 예시한다. 상기 스퍼터 타겟의 단차비(단차비 = 깊이/너비 = H/L로 정의됨)와 오목부(106a)의 너비(L)와 측벽(106b)의 파인 깊이(H) 등은 공정처리를 원하는 기판에 형성된 또는 형성하고자 하는 패턴의 크기, 모양, 단차 등을 고려하여 조절할 수 있다. 도 4에 예시된 단차구조에서, 중심선을 가로지르는 단면은 모두 도 3(c)에 도시된 단면을 갖는다.In the sputter target having a stepped structure, the cross section of the hole, that is, the cross section of the groove 106a may be implemented in various shapes that can regularly fill a plane such as a square, a circle, a pentagon, a hexagon, a straight line, a rhombus, and the like. . 4 is a view showing another embodiment of the step structure of the sputter target according to the present invention, illustrating a circle (Fig. 4 (a)), a hexagon (Fig. 4 (b)) and a straight (Fig. 4 (c)) . The step ratio of the sputter target (defined as step ratio = depth / width = H / L), the width L of the recess 106a and the fine depth H of the sidewall 106b are the substrates to be processed. It may be adjusted in consideration of the size, shape, step, etc. of the pattern formed or to be formed on. In the stepped structure illustrated in FIG. 4, the cross sections across the centerline all have the cross section shown in FIG. 3 (c).
도 5는 본 발명의 또 다른 실시예에 따른 스퍼터 타겟의 단차구조를 보여주는 도면으로서, 도 5(a)은 상기 스퍼터 타겟의 사시도이고, 도 5(b)는 평면도이고, 도 5(c)는 도 5(b)의 A-A' 선을 따라 절단한 상기 스퍼터 타겟의 절단단면도이다. 도 5에서 동일한 깊이와 너비를 갖는 복수의 오복부들로 구성되는 오목부 그룹을 포함하고, 서로 상이한 너비(L) 또는 단차비(H/L)를 갖는 두 개 이상의 오목부 그룹들이 규칙적으로 조합 배열되어 형성된 단차구조를 포함하는 스퍼터 타겟을 보여준다. 두 개 이상의 오목부 그룹을 포함하는 단차구조를 갖는 스퍼터 타겟(106)은 플라즈마 이온에 의해 방출되는 스퍼터 타겟 구성재료 입자의 반사 각도 범위와 각각의 양을 조절할 수 있도록 한다.5 is a view showing a stepped structure of a sputter target according to another embodiment of the present invention, Figure 5 (a) is a perspective view of the sputter target, Figure 5 (b) is a plan view, Figure 5 (c) is A cross-sectional view of the sputter target cut along the line AA ′ of FIG. 5 (b). In FIG. 5, a concave group consisting of a plurality of recesses having the same depth and width, and two or more concave groups having different widths (L) or step ratios (H / L) are regularly arranged in combination. To show a sputter target including a stepped structure. The sputter target 106 having a stepped structure including two or more concave groups can adjust the amount of each and the reflection angle range of the sputter target constituent particles emitted by the plasma ions.
실시예EXAMPLE
이하 구체적 실시예를 통하여 본 발명을 보다 구체적으로 설명한다. 다만, 이들 실시예는 본 발명의 이해를 위해서 제시된 것으로서 본 발명의 범위가 이들 실시예에 한정되는 것은 아니다.Hereinafter, the present invention will be described in more detail with reference to specific examples. However, these examples are presented for the understanding of the present invention, and the scope of the present invention is not limited to these examples.
본 발명에서 사용된 스퍼터 타겟은 2대1의 단차를 갖는 복수의 원통형 홀들이 표면에 규칙적으로 배열되어 있다. 각 구멍은 3mm 지름에 6mm 깊이이고 구멍 사이의 간격은 2mm로 구성되어 있으며, 이로 인해 스퍼터되어 나오는 입자들은 2대 1의 단차비가 만드는 각도에 의해 구멍내 스퍼터빔의 각도를 약 26.5도 이하로 제어할 수 있게 된다. 타겟의 오목부가 가지는 단차비에 따라서 제어하는 빔의 각도가 달라지기 때문에 증착하려는 고단차 트렌치에 맞는 적절한 단차비를 형성하는 것이 가능하다.In the sputter target used in the present invention, a plurality of cylindrical holes having a 2 to 1 step are regularly arranged on the surface. Each hole is 3mm in diameter and 6mm deep and the spacing between holes is 2mm, which causes the sputtered particles to control the angle of sputter beam in the hole to about 26.5 degrees or less by the angle created by the ratio of two to one. You can do it. Since the angle of the beam to be controlled varies according to the step difference ratio of the recess of the target, it is possible to form an appropriate step ratio suitable for the high step trench to be deposited.
플라즈마 소스로서 고진공의 리지타노-코일 ECR (Lisitano -coil ECR) 플라즈마 소스를 사용하였다. ECR 플라즈마의 특징 중 하나는 높은 이온화율을 위한 고밀도 플라즈마(1010 ~ 1012 cm-3)를 형성하는 것이고 또한 1 mTorr이하의 압력에서도 동작할 수 있는 특징을 가지고 있다. 이들은 플라즈마 방전 공간의 측면에 배치된다.As the plasma source, a high vacuum Lisitano-coil ECR plasma source was used. One of the characteristics of ECR plasma is to form a high density plasma (10 10 ~ 10 12 cm -3 ) for high ionization rate, and also can operate at a pressure of 1 mTorr or less. They are arranged on the side of the plasma discharge space.
증착 실험을 위한 실험 조건은 다음과 같다. 플라즈마 형성을 위해700W 크기의 마이크로웨이브 파워와 1 mTorr의 공정 압력을 유지하기 위한 아르곤(Ar) 가스 5 sccm을 공급하였다. 스퍼터 타겟은 800 V의 음의 DC 바이어스를, 그리고 필요에 따라 기판에 RF 파워를 0~50 W를 인가하여 증착된 기판의 리스퍼터링(re-sputtering) 효과를 관찰하였다. 증착 후, 시편 단면의 형태(morphology) 확인은 주사전자현미경(scanning electron microscopy, SEM)을 이용하여 분석하였다. SEM을 통해 확인된 벽면의 구리 증착 두께와 트렌치 각 지점의 개구부에 대한 각도를 조사하여 스퍼터빔의 각도에 따른 분포와 벽면 위치에 따른 증착량을 비교 분석하여 보았다.Experimental conditions for the deposition experiment are as follows. For plasma formation, 5 sccm of argon (Ar) gas was supplied to maintain a microwave power of 700 W and a process pressure of 1 mTorr. The sputter target was subjected to a negative DC bias of 800 V and, if necessary, RF power of 0-50 W to the substrate to observe the re-sputtering effect of the deposited substrate. After deposition, the morphology of the cross section of the specimen was analyzed by scanning electron microscopy (SEM). The copper deposition thickness of the wall and the angles of the openings of each trench point were examined by SEM, and the distribution according to the angle of the sputter beam and the deposition amount according to the wall location were compared.
다음으로 스퍼터 타겟 표면이 가지는 단차구조에 의한 스퍼터된 빔의 직진성 향상 정도와 증착 특성에 미치는 영향을 살펴보고자 한다. 도 6은 일반적인 스퍼터 타겟과 본 발명의 스퍼터 타겟을 이용하여 동일 조건에서 증착한 구리 박막의 단면을 보여주는 SEM 사진이고, 도 7은 도 6의 일부를 확대한 SEM 사진이다. 도 6및 7에서 (a)는 종래의 스퍼터 타겟에 의한 실험결과, (b)는 본 발명의 단차구조를 갖는 스퍼터 타겟의 실험결과를 각각 보여준다. 도 6 및 도 7에서 보는 것과 같이, 단차구조를 갖는 스퍼터 타겟을 이용한 증착이 벽면 상단에 구리의 증착량이 (a)보다 줄어듦과 동시에 바닥면에 구리 증착량이 늘어남을 알 수 있다(도 7(b)에서 보다 자세히 보여짐). 이것은 스퍼터 타겟에 형성되어 있는 단차구조에 의해 스퍼터되어 나오는 입자들의 각도가 보다 수직에 가까운 형태로 내려오기 때문에 빔의 직진성이보다 강화된 것으로 확인된다.Next, the effect of the stepped structure of the sputter target surface on the degree of linearity improvement and deposition characteristics of the sputtered beam will be examined. 6 is a SEM photograph showing a cross section of a copper thin film deposited under the same conditions using a general sputter target and the sputter target of the present invention, and FIG. 7 is an enlarged SEM photograph of a portion of FIG. 6. 6 and 7 (a) shows the experimental results of the conventional sputter target, (b) shows the experimental results of the sputter target having a stepped structure of the present invention, respectively. As shown in FIG. 6 and FIG. 7, it can be seen that the deposition using the sputter target having the stepped structure reduces the amount of copper deposited on the top of the wall rather than (a) and at the same time, the amount of copper deposited on the bottom (FIG. 7 (b). )). It is confirmed that the straightness of the beam is enhanced because the angle of the sputtered particles is lowered to a more vertical form by the stepped structure formed on the sputter target.
일반적으로 스퍼터된 입자는 (cosθ)n의 분포로 스퍼터되어 나오므로 타겟의 수직한 방향으로 가장 많은 양이 나오고 수직각에서 멀어질수록 (cosθ)n에 비례하여 줄어들게 된다(n은 0.5-2; 일반적으로 n~1). 입사각의 영향에 따른 증착 두께를 보다 명확히 확인하기 위해, 일반적인 스퍼터 타겟(normal sputtertarget)과 본 발명에 의한 스퍼터 타겟의 입사각에 따른 증착 두께를 비교하였으며, 그 결과를 도 8에 나타내었다. 도 8을 통해, 실험에 사용된 구리 증착 패턴을 사용하여 스퍼터된 빔의 분포가 예상되는 일반적인 cosθ에 비하여 얼마나 차이가 나는지 알 수 있다. 여기서 파란색으로 표시된 점선은 cosθ로 빔이 내려올 때 증착된 두께를 각도에 따라 적분한 값에 해당하는 sinθ 곡선을 나타내고 노란색 실선은 단차구조 타겟을 통해 26.5도 이내로 빔이 내려올 때 예상되는 증착 곡선이다. 트렌치 각점에서 증착된 두께를 개구부에 대한 열린 각도에 따라 표시하면 일반적 스퍼터 타겟과 본 발명의 새로운 스퍼터 타겟이 모두 예상치와 비교적 잘 일치하는 것을 볼 수 있다. 이것을 증착 패턴의 벽면(sidewall) 위치(여기서, 수평축에 표시된 벽면 위치 0은 벽면의 상단 끝, 5는 벽면의 바닥끝을 나타낸다)에 따른 두께를 확인해 보면, 도 9에서 보는 것과 같이, 본 발명의 스퍼터 타겟이 상단부의 증착량이 줄어들어 벽면의 상단부와 하단부 두께가 보다 균일해 지는 것을 확인하였다.In general, the sputtered particles are sputtered with a distribution of (cosθ) n , so that the largest amount comes out in the vertical direction of the target and decreases in proportion to (cosθ) n as the distance from the vertical angle (n is 0.5-2; Generally n ~ 1). In order to more clearly identify the deposition thickness according to the influence of the incident angle, the deposition thickness according to the incident angle of the normal sputter target and the sputter target according to the present invention were compared, and the results are shown in FIG. 8. 8, it can be seen how the difference in the distribution of the sputtered beam compared to the general cos θ is expected using the copper deposition pattern used in the experiment. Here, the dotted line in blue represents the sinθ curve corresponding to the integral value of the deposited thickness according to the angle when the beam descends to cosθ, and the solid yellow line is the expected deposition curve when the beam descends within 26.5 degrees through the stepped target. Indication of the thickness deposited at each trench point according to the open angle to the opening shows that both the general sputter target and the new sputter target of the present invention are relatively in good agreement with the expectation. Checking the thickness according to the sidewall position of the deposition pattern (where wall position 0 indicated on the horizontal axis is the top end of the wall and 5 is the bottom end of the wall), as shown in FIG. As the sputter target was reduced in the amount of deposition on the upper end, it was confirmed that the thickness of the upper end and the lower end of the wall became more uniform.
도 10은 종래기술에 의해 증착된 TaN 배리어를 보여주는 TEM 단면 사진으로서, 도 10에서 보여지는 미국의 노벨러스(Novellus)에서 2009년에 발표한 TEM 단면사진(a)과 Applied materials(AMAT)사에서 2007년에 발표한 TEM 단면사진(b)을 비교하면 도 11에서 보는 것과 같이 두 회사의 스퍼터된 빔이 cosθ의 분포를 따라 가고, 낮은 입사각 혹은 단차구조의 바닥에 가까운 곳에서 벽면증착을 보정하기 위해 기판에 걸어주는 바이어스(bias)에 의해 리스퍼터링(re-sputtering)이 일어나 일반적인 스퍼터링 곡선에서 리스퍼터링(re-sputtering)만큼 차이가 나는 것이 확인된다. 도 12에서, 벽면(sidewall)위치에 대한 두께에 있어서도 본 발명에 따른 단차구조를 갖는 스퍼터 타겟을 이용하여 박막을 증착하는 경우에 AMAT나 Novellus의 종래기술보다 50% 이상의 균일한 두께를 형성함으로써 현재 가장 앞선 기술보다도 더 우수함이 입증되고 있다.FIG. 10 is a TEM cross-sectional view showing a TaN barrier deposited by the prior art, and a TEM cross-section (a) and Applied materials (AMAT) published in 2009 by Novellus, USA, shown in FIG. Comparing the TEM cross-section picture (b) published in 2011, as shown in Fig. 11, the sputtered beams of the two companies follow the distribution of cosθ, and to correct wall deposition at a low incident angle or near the bottom of the stepped structure. Re-sputtering occurs due to bias applied to the substrate, and it is confirmed that the difference is as much as re-sputtering in the general sputtering curve. In Fig. 12, in the case of a thin film deposited using a sputter target having a stepped structure according to the present invention in terms of thickness on a sidewall position, the present invention is formed by forming a uniform thickness of 50% or more than that of AMAT or Novellus. It is proven to be superior to the most advanced technology.
본 발명에 따른 스퍼터 타겟을 사용하여, 스퍼터된 빔 각도에 따른 분포도와 패턴의 벽면위치 별 구리 증착 두께를 비교한 결과, 타겟에 형성되어 있는 단차구조에 의해 스퍼터 빔의 직진성이 보다 향상됨을 확인하였고, 스텝 커버리지가 50% 이상 향상 되었다. 이것은 고단차의 구리 배선용 씨앗층을 보다 균일하고 연속적인 구리 박막을 증착하기에 보다 적합한 것으로 보여진다. 이러한 결과는 본 발명에 따른 단차구조를 갖는 스퍼터 타겟이 다양한 표면증착에 효과적으로 응용될 수 있음을 의미한다. As a result of comparing the distribution according to the sputtered beam angle and the copper deposition thickness according to the wall position of the pattern using the sputter target according to the present invention, it was confirmed that the straightness of the sputter beam is improved by the stepped structure formed on the target. In addition, step coverage has been improved by more than 50%. This appears to be more suitable for depositing higher-level copper wiring seed layers to deposit more uniform and continuous copper thin films. This result means that the sputter target having the stepped structure according to the present invention can be effectively applied to various surface depositions.
본 실시예 및 본 명세서에 첨부된 도면은 본 발명에 포함되는 기술적 사상의 일부를 명확하게 나타내고 있는 것에 불과하며, 본 발명의 명세서 및 도면에 포함된 기술적 사상의 범위 내에서 당업자가 용이하게 유추할 수 있는 변형 예와 구체적인 실시 예는 모두 본 발명의 권리범위에 포함되는 것이 자명하다고 할 것이다. The embodiments and drawings attached to this specification are merely to clearly show some of the technical ideas included in the present invention, and those skilled in the art can easily infer within the scope of the technical ideas included in the specification and drawings of the present invention. Modifications that can be made and specific embodiments will be apparent that both are included in the scope of the invention.

Claims (6)

  1. 플라즈마 방전 공간을 포함하는 스퍼터링 장치에 사용되는 스퍼터 타겟으로서, As a sputter target used for the sputtering apparatus containing a plasma discharge space,
    상기 플라즈마 방전 공간에 대향하는 스퍼트 타겟의 표면으로부터 내측으로 일정한 깊이(H)와 너비(L)를 갖도록 형성되어 측벽에 의해서 둘러싸이는 복수의 오목부; 및 A plurality of recesses formed to have a predetermined depth H and a width L inwardly from a surface of the spur target facing the plasma discharge space and surrounded by sidewalls; And
    상기 복수의 오목부가 규칙적으로 배열되어 구성되는 단차구조를 포함하는 It includes a stepped structure that is configured by the plurality of recesses arranged regularly
    스퍼터 타겟. Sputter Target.
  2. 제1항에 있어서, 상기 단차구조는 동일한 깊이와 너비를 갖는 복수의 오복부들로 구성되는 오목부 그룹을 포함하고, 서로 상이한 너비(L) 또는 단차비(H/L)를 갖는 두 개 이상의 오목부 그룹들이 규칙적으로 조합 배열되어 형성된 스퍼터 타겟.The method of claim 1, wherein the stepped structure includes a recess group consisting of a plurality of recesses having the same depth and width, and at least two recesses having different widths (L) or step ratios (H / L) from each other. A sputter target formed by regularly combining subgroups.
  3. 제1항에 있어서, 상기 복수의 오목부의 너비는 플라즈마 쉬쓰(plasma sheath) 두께 보다는 크게 형성된 스퍼터 타겟.The sputter target of claim 1, wherein a width of the plurality of recesses is greater than a plasma sheath thickness.
  4. 제1항 내지 제3항 중 어느 한 항에 따른 스퍼터 타겟을 포함하는 스퍼터링 장치.A sputtering apparatus comprising the sputter target according to any one of claims 1 to 3.
  5. 플라즈마 방전 공간, 스퍼터 타겟, 및 상기 플라즈마 방전공간에서 생성된 플라즈마를 상기 스퍼터 타겟으로 유도하는 수단을 포함하는 스퍼터링 장치에 있어서, 상기 스퍼터 타겟이 A sputtering apparatus comprising a plasma discharge space, a sputter target, and means for guiding a plasma generated in the plasma discharge space to the sputter target, wherein the sputter target is
    상기 플라즈마가 유도되는 상기 스퍼터 타겟의 표면으로부터 내측으로 일정한 깊이(H)와 너비(L)를 갖도록 형성되어 측벽에 의해서 둘러싸이는 복수의 오목부; 및 상기 복수의 오목부가 규칙적으로 배열되어 구성되는 단차구조를 포함하는 스퍼터링 장치.A plurality of recesses formed to have a constant depth H and a width L inward from a surface of the sputter target from which the plasma is induced and surrounded by sidewalls; And a stepped structure in which the plurality of recesses are regularly arranged.
  6. 제5항에 있어서, 상기 복수의 오목부의 너비는 플라즈마 쉬쓰(plasma sheath) 두께 보다는 크게 형성된 스퍼터링 장치.The sputtering apparatus of claim 5, wherein a width of the plurality of recesses is greater than a plasma sheath thickness.
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Citations (2)

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KR100231397B1 (en) * 1991-01-28 1999-11-15 튜그룰 야사르 Target for cathode sputtering
JP2005126783A (en) * 2003-10-24 2005-05-19 Olympus Corp Sputtering target

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JPS61117276A (en) * 1984-11-14 1986-06-04 Hitachi Ltd Target for sputtering
JPS61291964A (en) * 1985-06-17 1986-12-22 Anelva Corp Resin target for sputtering
JPH05125531A (en) * 1990-10-23 1993-05-21 Internatl Business Mach Corp <Ibm> Sputtering deposition apparatus and sputtering cathode
JPH05230642A (en) * 1992-02-21 1993-09-07 Nissin High Voltage Co Ltd Sputtering target

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100231397B1 (en) * 1991-01-28 1999-11-15 튜그룰 야사르 Target for cathode sputtering
JP2005126783A (en) * 2003-10-24 2005-05-19 Olympus Corp Sputtering target

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