WO2013024971A2 - Cmp slurry composition for tungsten polishing - Google Patents

Cmp slurry composition for tungsten polishing Download PDF

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Publication number
WO2013024971A2
WO2013024971A2 PCT/KR2012/005397 KR2012005397W WO2013024971A2 WO 2013024971 A2 WO2013024971 A2 WO 2013024971A2 KR 2012005397 W KR2012005397 W KR 2012005397W WO 2013024971 A2 WO2013024971 A2 WO 2013024971A2
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Prior art keywords
tungsten
polishing
weight
slurry composition
slurry
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PCT/KR2012/005397
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French (fr)
Korean (ko)
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WO2013024971A3 (en
Inventor
박재근
박진형
임재형
조종영
최호
황희섭
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(주)유비프리시젼
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Priority claimed from KR1020110117872A external-priority patent/KR101335946B1/en
Application filed by (주)유비프리시젼 filed Critical (주)유비프리시젼
Priority to CN201280001134.4A priority Critical patent/CN103228756B/en
Priority to JP2013529087A priority patent/JP5766289B2/en
Priority to US13/643,375 priority patent/US9163314B2/en
Publication of WO2013024971A2 publication Critical patent/WO2013024971A2/en
Publication of WO2013024971A3 publication Critical patent/WO2013024971A3/en

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    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/32115—Planarisation
    • H01L21/3212—Planarisation by chemical mechanical polishing [CMP]
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09G—POLISHING COMPOSITIONS; SKI WAXES
    • C09G1/00—Polishing compositions
    • C09G1/02—Polishing compositions containing abrasives or grinding agents
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00—Materials not provided for elsewhere
    • C09K3/14—Anti-slip materials; Abrasives
    • C09K3/1454—Abrasive powders, suspensions and pastes for polishing
    • C09K3/1463—Aqueous liquid suspensions
    • 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
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
    • H01L21/7684—Smoothing; Planarisation

Definitions

  • the present invention relates to a slurry composition used in a chemical mechanical polishing (CMP) process in a semiconductor fabrication process, and more particularly to a CMP slurry composition that can be used for planarization of a tungsten metal film.
  • CMP chemical mechanical polishing
  • a CMP process is mainly used for wide area planarization of a wafer surface.
  • the CMP process is a polishing method in which the surface of a wafer is planarized using a polishing pad and a slurry during semiconductor manufacturing.
  • An orbital motion in which a slurry composition is dropped on a polishing pad made of polyurethane and is in contact with a wafer is mixed with rotational and linear motion. It is a step of polishing the wafer mechanically and chemically by performing the.
  • the slurry generally contains an abrasive which is physically abrasive and an active component which is chemically abrasive, for example an etchant or an oxidant, so that the physicochemically protruding portion on the wafer surface Selective etching may provide a flat surface.
  • CMP slurry can be divided into insulating layer polishing slurry and metal polishing slurry, depending on the polishing object.
  • the insulating layer polishing slurry is applied to ILD (interlayer dielectric) process and shallow trench isolation (STI) process during semiconductor process.
  • ILD interlayer dielectric
  • STI shallow trench isolation
  • Metallurgical polishing slurries are used for the formation of interconnects and tungsten contacts / via plugs of tungsten, aluminum or copper wiring or for dual damascene processes.
  • FIG. 1 shows a flowchart of a manufacturing process of a semiconductor device to which a tungsten CMP slurry composition according to the present invention is applied.
  • a tungsten (W) film is deposited on the entire surface so that the contact hole is completely filled.
  • an adhesive layer made of Ti is formed on the surface of the semiconductor substrate before depositing the tungsten film, and the Ti having high reactivity with the source material WF 6 when forming the tungsten film
  • a barrier metal film of TiN is further formed on the adhesive layer to prevent inter-bonding.
  • a tungsten film on the SiO 2 oxide film is polished by a first chemical mechanical polishing (CMP) process using a metal slurry to form a tungsten plug in the contact hole.
  • CMP chemical mechanical polishing
  • a second soft CMP process using an oxide slurry is performed for several seconds to several tens of seconds to remove the oxidative defect on the tungsten plug and to polish the SiO 2 oxide film to a predetermined thickness.
  • the primary metal polishing slurry generally includes an abrasive, an oxidizing agent, an oxidizing aid, a dispersant, a pH adjuster, other additives, etc.
  • the abrasive is for mechanical polishing
  • the oxidizing agent and the oxidizing aid are for promoting the polishing through the oxidation of the metal layer
  • the dispersing agent serves to improve the dispersion stability of the slurry
  • the pH adjuster adjusts the pH range where oxidation can occur well depending on the nature of the metal layer to be polished
  • various additives may be included to improve or supplement the performance of other slurries.
  • the tungsten CMP process uses a slurry containing an oxidizing agent.
  • a strong oxidizing agent such as hydrogen peroxide (H 2 O 2 ) and iron nitrate (FeNO 3 ) is mixed with a slurry containing an abrasive such as silica and alumina particles. I use it.
  • the oxidant in the slurry oxidizes the tungsten surface to make tungsten oxide (WO 3 ) and WO 3 is much weaker than W and can be easily removed with an abrasive.
  • tungsten CMP process In the tungsten CMP process, WO 3 is removed by mechanical polishing by an abrasive in a slurry and a CMP pad, and the tungsten film 15 is removed while repeating a process in which the metal W under the WO 3 layer is changed to WO 3 by an oxidant and continuously removed. .
  • the metal barrier film 14 is also removed by a mechanism similar to tungsten polishing.
  • the slurry is designed in consideration of the aspects of speeding up the oxidation process or smoothly removing the formed oxide.
  • the metal polishing slurry should have a difference in polishing rates in the metal layer and the insulating layer. Therefore, a high polishing rate is required in the metal wiring, and a low polishing rate is required in the insulating layer. This is because when the speed difference is small, only a portion having a high pattern density may have a high polishing rate, and defects such as erosion may occur at a high pattern density. Therefore, the polishing rate of the insulating layer should be lowered to prevent the partial polishing rate increase phenomenon.
  • Cabot Patent Registration 10-0745447 describes a chemical mechanical polishing precursor composition comprising a catalyst and a stabilizer having multiple oxidation states useful for removing metal layers from a substrate by mixing with an oxidant. It contains iron.
  • the removal rate of the tungsten film that is, the polishing selectivity is very large, from 50 to 150, relative to the removal rate of the interlayer insulating film. Excessive plug recesses occur and the roughness of the plug surface of the CMP is increased.
  • a metal catalyst containing iron nitrate there is a problem that the pad contamination due to discoloration occurs, there is a need for the development of a CMP slurry that can improve this.
  • the present invention is a tungsten polishing CMP slurry composition
  • a tungsten polishing CMP slurry composition comprising an abrasive and an abrasive accelerator, wherein the abrasive comprises colloidal silica dispersed in ultrapure water, the abrasive promoter is hydrogen peroxide, ammonium persulfate and nitric acid It provides a tungsten polishing CMP slurry composition comprising iron.
  • the content of the colloidal silica is preferably 2 to 4% by weight.
  • the content of iron nitrate is preferably 0.01 to 0.1% by weight.
  • an etching selectivity of tungsten and titanium nitride is 1: 1.5 to 2
  • an etching selectivity of tungsten and oxide film is 2: 1 or more to provide a tungsten polishing CMP slurry composition.
  • the pH of the composition is preferably 2-4.
  • the tungsten polishing CMP slurry composition according to the present invention contains iron nitrate, hydrogen peroxide, and ammonium persulfate in an appropriate composition ratio, and thus the problem of discoloration occurring when a slurry composition containing an excess of conventional iron nitrate is used in the CMP process. While solving, the etching selectivity with titanium nitride and the oxide film is excellent, it can be effectively used in the tungsten CMP process.
  • FIG. 1 is a schematic diagram of a general tungsten CMP process to which the slurry composition according to the present invention is applied.
  • Figure 2 is a graph showing the polishing rate for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 1.
  • Figure 3 is a graph showing the polishing rate for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 2.
  • Figure 4 is a graph of the removal rate (3a) and slurry discoloration (3b) for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 3.
  • Figure 5 is a photograph showing the color change results with increasing concentration of iron nitrate.
  • Figure 6 is a graph showing the polishing rate for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 4.
  • Figure 7 is a graph showing the polishing rate for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 5.
  • Figure 8 is a graph showing the polishing rate for W, TiN, Oxide according to the APS concentration change of the CMP slurry composition according to the embodiment.
  • FIG 9 is a graph showing the polishing rate according to the iron nitrate concentration change of the CMP slurry composition according to the embodiment.
  • the tungsten polishing CMP slurry composition according to the present invention comprises an abrasive and an abrasive accelerator, wherein the abrasive comprises colloidal silica dispersed in ultrapure water, and the abrasive accelerator comprises hydrogen peroxide, ammonium persulfate and iron nitrate. to be.
  • the content of the colloidal silica is preferably 2 to 4% by weight. If the colloidal silica content is 2 wt% or less, the polishing rate is low, and if it is 4 wt% or more, there is a high possibility of scratching.
  • the content of hydrogen peroxide water is preferably from 0.5 to 2% by weight.
  • the content of hydrogen peroxide is 0.5% by weight or less, tungsten is not oxidized, the polishing rate is reduced, and when it is 2% by weight or more, tungsten oxide is saturated, so the hydrogen peroxide concentration of 2% by weight or more is not significant.
  • the content of the ammonium persulfate is preferably 0.05 to 1% by weight. If the amount of ammonium persulfate is 0.05% by weight or less, the selectivity between TiN and W is similar, and thus not suitable for the CMP process.
  • the content of iron nitrate is preferably 0.01 to 0.1% by weight.
  • the content of iron nitrate is more than 0.1% by weight, slurry discoloration may occur, and when the CMP process is applied, pad contamination may occur, and when the content is less than 0.01% by weight, the tungsten polishing rate is difficult to use.
  • an etching selectivity of tungsten and titanium nitride is 1: 1.5 to 2
  • an etching selectivity of tungsten and oxide film is 2: 1 or more to provide a tungsten polishing CMP slurry composition.
  • the tungsten plug is attached to the tungsten plug when the etching selectivity of tungsten and titanium nitride is 1: 1.5 or less or 1: 2 or more, and the etching selectivity of tungsten and oxide film is 2: 1 or less. The effect is generated.
  • the pH of the composition is preferably 2-4. If the pH is less than 2, it is difficult and dangerous to handle with a strong acid, and if the pH is higher than 4, corrosion pit is formed on the surface due to polishing by corrosion rather than polishing by tungsten oxide formation.
  • As a polishing machine G & P Tech company's poli-300 machine was used, and as the polishing pad, Rohm & Haas's IC 1000 / Suba IV CMP pad was used.
  • Grinding conditions include a down pressure of 2.5 psi, table and spindle speeds of 90 rpm, and slurry flow rates of 100 mL / min, polishing tungsten, titanium nitride, and silicon films at 60, 30, and 60 s, respectively. It was.
  • colloidal silica As abrasive particles, colloidal silica (Fuso, PL-7) having a primary particle size of 75 nm and a secondary particle size of 215 nm was used in 4 wt%, which was evenly dispersed in ultrapure water. 1% by weight of hydrogen peroxide (JunSei) was used as the oxidizing agent, and iron (III) nitrate (Sigma-Aldrich) was used as an oxidation promoter, and ammonium persulfate (Sigma-Aldrich) was used to improve the etching selectivity. The pH of the slurry was 2-3.
  • Comparative Example 1 was used as a slurry to which only 2% by weight of H 2 O 2 generally used in a CMP process was used.
  • polishing of W, TiN, and Oxide of the slurry composition of Comparative Example 1 was performed. The rate is shown.
  • Oxidizing agent (1) Oxidizing agent (2) 4% by weight of colloidal silica (PL-7) APS 2% by weight 2 % by weight of H 2 O 2
  • the discoloration point of the slurry was found by changing the concentration of Fe (NO 3 ) 3.
  • the concentration of Fe (NO 3 ) 3 As a result, as shown in FIG. 5, when the Fe (NO 3 ) 3 0.1 wt% or more is added, the color gradually changes. it started.
  • iron nitrate at 0.1 weight% or less.
  • the polishing rate for W, TiN, and Oxide was measured as Comparative Example 4, except that 0.01 wt% of Fe (NO 3 ) 3 and APS concentration were excluded except for H 2 O 2 . As shown in FIG. 6, the removal rate of tungsten was very low.
  • Oxidizing agent (1) Oxidizing agent (2) 4% by weight of colloidal silica (PL-7) Fe (NO 3 ) 3 0.01% by weight APS 0 ⁇ 0.05% by weight
  • the polishing rate increased sharply from 750 to 1150 ⁇ / min as the Fe (NO 3 ) 3 concentration increased from 0 to 0.03% by weight, and 1150 to 1830 ⁇ / min as the concentration increased from 0.03 to 1% by weight.
  • the polishing rate increased little by little.
  • the polishing rate increased rapidly from 1630 to 2580 ⁇ / min, and then increased from 2580 ⁇ / min when the concentration was increased above 0.03% by weight.
  • the polishing rate decreased so that the polishing rate decreased from 1% by weight of Fe (NO 3 ) 3 to 2030 dl / min.
  • Oxide showed a removal rate of 500 to 600 ⁇ / min without significant change in the etching rate according to the Fe (NO 3 ) 3 concentration.
  • Example 1 CMP Slurry Composition Comprising Hydrogen Peroxide, Iron Nitrate, Ammonium Persulfate
  • a slurry composition having a composition of Table 6 was prepared according to the necessity of developing a new slurry and a new slurry that would not discolor and reduce the titanium nitride removal rate.

Abstract

The present invention relates to a CMP slurry composition for tungsten polishing containing abrasives and polishing accelerators, wherein the abrasive comprises colloidal silica dispersed in ultrapure water and the polishing accelerator comprises aqueous hydrogen peroxide, ammonium persulfate, and ferric nitrate. The slurry composition does not cause a slurry discoloration problem and can be applied to a CMP process due to having excellent etch selectivity.

Description

텅스텐 연마용 ＣＭＰ 슬러리 조성물Tungsten Polishing CPM Slurry Composition
본 발명은 반도체 제조　공정 중 CMP(Chemical Mechanical Polishing) 공정에서 사용되는 슬러리 조성물에 관한 것으로서, 특히 텅스텐 금속막의 평탄화에 사용될 수 있는 CMP 슬러리 조성물에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slurry composition used in a chemical mechanical polishing (CMP) process in a semiconductor fabrication process, and more particularly to a CMP slurry composition that can be used for planarization of a tungsten metal film.
집적회로의 다중막 연마공정 또는 이중상감공정 등에서는 웨이퍼 표면의 광역 평탄화를 위해 주로 CMP 공정이 사용된다. CMP 공정이란, 반도체 제조시 웨이퍼 표면을 연마패드와 슬러리를 사용하여 평탄화하는 연마 방법으로, 폴리우레탄 재질의 연마패드 상에 슬러리 조성물을 떨어뜨리고 웨이퍼와 접촉시킨 후 회전 및 직선 운동을 혼합한 오비탈 운동을 실시하여 웨이퍼를 기계적 및 화학적으로 연마하는 공정이다.In the multilayer film polishing process or the double damascene process of an integrated circuit, a CMP process is mainly used for wide area planarization of a wafer surface. The CMP process is a polishing method in which the surface of a wafer is planarized using a polishing pad and a slurry during semiconductor manufacturing. An orbital motion in which a slurry composition is dropped on a polishing pad made of polyurethane and is in contact with a wafer is mixed with rotational and linear motion. It is a step of polishing the wafer mechanically and chemically by performing the.
CMP 공정에서 상기 슬러리는 일반적으로 물리적 연마작용을 하는 연마제(abrasive) 및 화학적 연마작용을 하는 활성 성분, 예를 들어 에천트(etchant) 또는 산화제를 포함하고 있어, 물리화학적으로 웨이퍼 표면 상의 돌출된 부분을 선택적으로 식각함으로써 평탄한 표면을 제공하게 된다.In the CMP process, the slurry generally contains an abrasive which is physically abrasive and an active component which is chemically abrasive, for example an etchant or an oxidant, so that the physicochemically protruding portion on the wafer surface Selective etching may provide a flat surface.
CMP 슬러리는 연마대상에 따라 절연층 연마용 슬러리와 금속 연마용 슬러리로 나눌 수 있는데, 이 중, 절연층 연마용 슬러리는 반도체 공정 중 ILD (interlayer dielectric) 공정, STI(Shallow trench isolation) 공정에 적용되고, 금속 연마용 슬러리는 텅스텐, 알루미늄 또는 구리배선의 연결점(interconnects) 및 텅스텐 접점/비아 플러그(contacts/via plug)의 형성시 혹은 이중 상감공정에 사용된다.CMP slurry can be divided into insulating layer polishing slurry and metal polishing slurry, depending on the polishing object. Among them, the insulating layer polishing slurry is applied to ILD (interlayer dielectric) process and shallow trench isolation (STI) process during semiconductor process. Metallurgical polishing slurries are used for the formation of interconnects and tungsten contacts / via plugs of tungsten, aluminum or copper wiring or for dual damascene processes.
도 1에 본 발명에 따른 텅스텐 CMP 슬러리 조성물이 적용되는 반도체 소자의 제조 공정의 순서도를 나타내었다.1 shows a flowchart of a manufacturing process of a semiconductor device to which a tungsten CMP slurry composition according to the present invention is applied.
본 발명의 실시예에 따른 플래시 메모리 소자의 제조공정은 우선, 도 1에 도시하는 바와 같이 게이트 전극 및 소오스 플러그 콘택 영역, 드레인 플러그 콘택 영역 등의 소정 구조물이 형성된 반도체 기판, 실리콘 기판상에 1000 내지 2000Å의 두께로 SiO2 산화막을 형성하고, 상기 소오스 플러그 콘택 영역(106a)이 노출되도록 상기 SiO2 산화막을 식각하여 콘택홀을 형성한다.In the process of manufacturing a flash memory device according to an embodiment of the present invention, first, as shown in FIG. forming an SiO 2 oxide film to a thickness of 2000Å, and by etching the SiO 2 oxide film to be the source and the plug contact region (106a) is exposed to form a contact hole.
이어서, 도 1 에 도시하는 바와 같이, 상기 콘택홀이 완전히 매립되도록 전면에 텅스텐(W)막을 증착한다. 상기 텅스텐막과 SiO2 산화막 및 질화막과의 접착력을 좋게 하기 위하여 상기 텅스텐막을 증착하기 전에 반도체 기판의 표면상에 Ti로 된 접착층을 형성하고, 텅스텐막 형성시 소오스 물질인 WF6와 반응성이 높은 Ti간 결합을 방지하기 위하여 상기 접착층상에 TiN으로 된 베리어 금속막을 추가로 형성한다. 이어, 메탈 슬러리를 사용한 1차 CMP(Chemical Mechanical polishing) 공정으로 상기 SiO2 산화막 위의 텅스텐막을 연마하여 상기 콘택홀 내부에 텅스텐 플러그를 형성한다. 상기 1차 CMP 공정을 완료한 후에 반도체 기판을 보면, 텅스텐 플러그 위에 과산화수소수(H2O2)와 메탈 슬러리(metal slurry)간 화학 반응에 의한 산화성 디펙트(defect)가 심하게 발생된 상태이다.Next, as shown in FIG. 1, a tungsten (W) film is deposited on the entire surface so that the contact hole is completely filled. In order to improve the adhesion between the tungsten film and the SiO 2 oxide film and the nitride film, an adhesive layer made of Ti is formed on the surface of the semiconductor substrate before depositing the tungsten film, and the Ti having high reactivity with the source material WF 6 when forming the tungsten film A barrier metal film of TiN is further formed on the adhesive layer to prevent inter-bonding. Subsequently, a tungsten film on the SiO 2 oxide film is polished by a first chemical mechanical polishing (CMP) process using a metal slurry to form a tungsten plug in the contact hole. When the semiconductor substrate is completed after the first CMP process is completed, oxidative defects are severely generated by a chemical reaction between hydrogen peroxide (H 2 O 2 ) and a metal slurry on the tungsten plug.
이어, 상기 산화성 디펙트를 제거하기 위하여 옥사이드 슬러리를 이용하여 2차 소프트 CMP 공정을 수초 내지 수십 초간 실시하여 상기 텅스텐 플러그위의 산화성 디펙트를 제거하고 상기 SiO2 산화막을 일정 두께 연마한다.Subsequently, in order to remove the oxidative defect, a second soft CMP process using an oxide slurry is performed for several seconds to several tens of seconds to remove the oxidative defect on the tungsten plug and to polish the SiO 2 oxide film to a predetermined thickness.
이와 같은 반도체 소자의 제조 공정 중 상기 1차 금속 연마용 슬러리는 일반적으로 연마제, 산화제, 산화보조제, 분산제, pH 조절제, 기타 첨가제 등을 포함하고 있는데, 상기 성분 중 연마제는 기계적인 연마를 위한 것이고, 산화제와 산화보조제는 금속층의 산화를 통하여 연마를 촉진하기 위한 것이며, 분산제는 슬러리의 분산 안정성을 향상시키는 역할을 하고, pH 조절제는 연마대상인 금속층의 성질에 따라 산화가 잘 일어날 수 있는 pH 범위를 조절하며, 기타 슬러리의 성능을 개선하거나 보완할 수 있는 각종 첨가제가 포함될 수 있다.In the manufacturing process of such a semiconductor device, the primary metal polishing slurry generally includes an abrasive, an oxidizing agent, an oxidizing aid, a dispersant, a pH adjuster, other additives, etc. Among the components, the abrasive is for mechanical polishing, The oxidizing agent and the oxidizing aid are for promoting the polishing through the oxidation of the metal layer, the dispersing agent serves to improve the dispersion stability of the slurry, the pH adjuster adjusts the pH range where oxidation can occur well depending on the nature of the metal layer to be polished In addition, various additives may be included to improve or supplement the performance of other slurries.
텅스텐 CMP 공정은 산화제가 포함된 슬러리를 사용하는데, 일반적으로 실리카, 알루미나 미립자와 같은 연마제(abrasive)가 포함된 슬러리에 과산화수소(H2O2), 질산철(FeNO3)와 같은 강산화제를 혼합하여 사용하고 있다. 슬러리 내의 산화제는 텅스텐 표면을 산화시켜 산화텅스텐(WO3)으로 만들며 WO3 는 W에 비해 훨씬 강도가 약하여 연마제로 쉽게 제거할 수 있다. 텅스텐 CMP 공정에서는 슬러리 내의 연마제 및 CMP 패드에 의한 기계적 연마로 WO3를 제거하고 WO3 층 아래의 금속 W은 산화제에 의해 WO3 로 변하여 게속 제거되는 과정을 반복하면서 텅스텐막(15)을 제거한다. 그리고 금속 배리어막(14)도 텅스텐 연마와 비슷한 메커니즘에 의해 제거한다.The tungsten CMP process uses a slurry containing an oxidizing agent. In general, a strong oxidizing agent such as hydrogen peroxide (H 2 O 2 ) and iron nitrate (FeNO 3 ) is mixed with a slurry containing an abrasive such as silica and alumina particles. I use it. The oxidant in the slurry oxidizes the tungsten surface to make tungsten oxide (WO 3 ) and WO 3 is much weaker than W and can be easily removed with an abrasive. In the tungsten CMP process, WO 3 is removed by mechanical polishing by an abrasive in a slurry and a CMP pad, and the tungsten film 15 is removed while repeating a process in which the metal W under the WO 3 layer is changed to WO 3 by an oxidant and continuously removed. . The metal barrier film 14 is also removed by a mechanism similar to tungsten polishing.
금속 CMP 공정은 산화제에 의해 형성된 산화물을 연마　입자가 제거하는 과정이 반복해서 일어나는 것으로 알려져 있다. 따라서 연마율의 향상을 위해서는 산화　과정을 빠르게 하거나, 형성된 산화물을 원활하게 제거하는 측면을 고려하여 슬러리를 디자인하게 된다.In the metal CMP process, it is known that the process of polishing and removing the oxide formed by the oxidant repeatedly occurs. Therefore, in order to improve the polishing rate, the slurry is designed in consideration of the aspects of speeding up the oxidation process or smoothly removing the formed oxide.
손쉽게는 금속을 부식시키는 산화제의 농도를 증가시켜서 연마 속도를 향상시키는 방법이 있으나, 부식　속도의 상승에 따라 corrosion pit이나 contact 부분 등 소자의 전기적 특성을 위해 배선층을 형성해야 하는 부분에까지 부식이 발생하면서, 오히려 소자의 신뢰도와 수율을 감소시킬 수도 있다.There is an easy way to improve the polishing speed by increasing the concentration of the oxidizing agent that corrodes the metal.However, as the corrosion rate increases, the corrosion occurs to the part where the wiring layer must be formed for the electrical characteristics of the device such as corrosion pit or contact part. Rather, it can reduce the reliability and yield of the device.
금속 연마용 슬러리는 금속층과 절연층에서의 연마속도 차이를 가져야 하는 바, 금속 배선에서는 높은 연마속도가 요구되며, 절연층에서는 낮은 연마속도가 요구된다. 속도 차이가 적게 되면 패턴 밀도가 높은 부분만 부분적으로 연마속도가 높아지는 현상이 발생하여 패턴 밀도가 높은 곳에서 에로젼(erosion) 등의 결함이 발생될 수 있기 때문이다. 따라서, 절연층의 연마속도를 낮게 하여 부분적인 연마속도 증가현상을 방지해야 한다. The metal polishing slurry should have a difference in polishing rates in the metal layer and the insulating layer. Therefore, a high polishing rate is required in the metal wiring, and a low polishing rate is required in the insulating layer. This is because when the speed difference is small, only a portion having a high pattern density may have a high polishing rate, and defects such as erosion may occur at a high pattern density. Therefore, the polishing rate of the insulating layer should be lowered to prevent the partial polishing rate increase phenomenon.
현재 질산철을 포함하는 CMP 슬러리가 많이 사용되고 있다. 예를 들어 캐보트의 특허등록 10-0745447호에는 산화제와 혼합하여 기판으로부터 금속층을 제거하는데 유용한 다중 산화 상태를 갖는 촉매 및 안정화제를 포함하는 화학 기계적 연마 전구체 조성물이 기재되어 있으며, 사용된 촉매를 철을 포함하고 있다.Currently, many CMP slurries containing iron nitrate are used. For example, Cabot Patent Registration 10-0745447 describes a chemical mechanical polishing precursor composition comprising a catalyst and a stabilizer having multiple oxidation states useful for removing metal layers from a substrate by mixing with an oxidant. It contains iron.
그러나, 종래, 강산화제가 첨가된 슬러리가 텅스텐 표면에 직접 작용하여 강력한 산화반응을 일으키므로 층간 절연막의 제거 속도에 대한 텅스텐막의 제거 속도, 즉 연마 선택비(selectivity)가 50 내지 150으로 매우 크므로 과도한 플러그 리세스가 발생하며, CMP가 완료된 플러그 표면의 거칠기가 커지는 문제점이 있다. 또한, 질산철을 포함하는 금속 촉매를 사용할 경우 변색으로 인한 패드 오염이 발생하는 문제가 있어 이를 개선할 수 있는 CMP 슬러리 개발이 요구되고 있다. However, in the related art, since the slurry to which the strong oxidant is added acts directly on the surface of tungsten to generate a strong oxidation reaction, the removal rate of the tungsten film, that is, the polishing selectivity is very large, from 50 to 150, relative to the removal rate of the interlayer insulating film. Excessive plug recesses occur and the roughness of the plug surface of the CMP is increased. In addition, when using a metal catalyst containing iron nitrate, there is a problem that the pad contamination due to discoloration occurs, there is a need for the development of a CMP slurry that can improve this.
본 발명의 목적은 텅스텐 CMP 공정에 사용할 경우 변색으로 인한 패드 오염 등의 문제가 발생하지 않으며, 금속층간의 식각 선택비가 우수한 텅스텐 연마용 CMP 슬러리 조성물을 제공하는 것이다.It is an object of the present invention to provide a tungsten polishing CMP slurry composition having excellent etching selectivity between metal layers without problems such as pad contamination due to discoloration when used in a tungsten CMP process.
상기 목적을 달성하기 위하여, 본 발명은 연마제와 연마촉진제를 포함하는 텅스텐 연마용 CMP 슬러리 조성물로서, 상기 연마제는 초순수에 분산된 콜로이드 실리카를 포함하며, 상기 연마촉진제는 과산화수소수, 암모늄퍼설페이트 및 질산철을 포함하는 텅스텐 연마용 CMP 슬러리 조성물을 제공한다.In order to achieve the above object, the present invention is a tungsten polishing CMP slurry composition comprising an abrasive and an abrasive accelerator, wherein the abrasive comprises colloidal silica dispersed in ultrapure water, the abrasive promoter is hydrogen peroxide, ammonium persulfate and nitric acid It provides a tungsten polishing CMP slurry composition comprising iron.
본 발명의 일실시예에 의하면, 콜로이드 실리카의 함량은 2 ~ 4중량%인 것이 바람직하다.According to one embodiment of the present invention, the content of the colloidal silica is preferably 2 to 4% by weight.
또한 본 발명의 다른 일실시예에 의하면, 질산철의 함량은 O.01 ~ 0.1중량%인 것이 바람직하다.In addition, according to another embodiment of the present invention, the content of iron nitrate is preferably 0.01 to 0.1% by weight.
또한 본 발명의 다른 일실시예에 의하면, 텅스텐과 질화티타늄의 식각 선택비가 1: 1.5 ~ 2이고, 텅스텐과 산화막의 식각 선택비가 2: 1 이상인 텅스텐 연마용 CMP 슬러리 조성물을 제공한다. In addition, according to another embodiment of the present invention, an etching selectivity of tungsten and titanium nitride is 1: 1.5 to 2, and an etching selectivity of tungsten and oxide film is 2: 1 or more to provide a tungsten polishing CMP slurry composition.
또한 본 발명의 다른 일실시예에 의하면, 조성물의 pH는 2 ~ 4 인 것이 바람직하다. In addition, according to another embodiment of the present invention, the pH of the composition is preferably 2-4.
본 발명에 따른 텅스텐 연마용 CMP 슬러리 조성물은 질산철과 과산화수수소 및 암모늄퍼설페이트를 적정 조성비로 포함하며, 이에 따라 종래 질산철을 과량 함유하는 슬러리 조성물을 CMP 공정에 사용할 경우 발생하는 변색 문제를 해결하면서, 질화티타늄 및 산화막과의 식각 선택비가 우수하여 텅스텐 CMP 공정에 효과적으로 사용할 수 있다. The tungsten polishing CMP slurry composition according to the present invention contains iron nitrate, hydrogen peroxide, and ammonium persulfate in an appropriate composition ratio, and thus the problem of discoloration occurring when a slurry composition containing an excess of conventional iron nitrate is used in the CMP process. While solving, the etching selectivity with titanium nitride and the oxide film is excellent, it can be effectively used in the tungsten CMP process.
도 1은 본 발명에 따른 슬러리 조성물이 적용되는 일반적인 텅스텐 CMP 공정의 개요도이다. 1 is a schematic diagram of a general tungsten CMP process to which the slurry composition according to the present invention is applied.
도 2는 비교예 1에 따른 CMP 슬러리 조성물의 W, TiN, Oxide에 대한 연마율을 나타내는 그래프이다. Figure 2 is a graph showing the polishing rate for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 1.
도 3은 비교예 2에 따른 CMP 슬러리 조성물의 W, TiN, Oxide에 대한 연마율을 나타내는 그래프이다. Figure 3 is a graph showing the polishing rate for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 2.
도 4는 비교예 3에 따른 CMP 슬러리 조성물의 W, TiN, Oxide에 대한 연마율 그래프(3a) 및 슬러리 변색 사진(3b)이다. Figure 4 is a graph of the removal rate (3a) and slurry discoloration (3b) for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 3.
도 5는 질산철의 농도 증가에 따라 변색 결과를 보여주는 사진이다.Figure 5 is a photograph showing the color change results with increasing concentration of iron nitrate.
도 6은 비교예 4에 따른 CMP 슬러리 조성물의 W, TiN, Oxide에 대한 연마율을 나타내는 그래프이다. Figure 6 is a graph showing the polishing rate for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 4.
도 7은 비교예 5에 따른 CMP 슬러리 조성물의 W, TiN, Oxide에 대한 연마율을 나타내는 그래프이다. Figure 7 is a graph showing the polishing rate for W, TiN, Oxide of the CMP slurry composition according to Comparative Example 5.
도 8은 실시예에 따른 CMP 슬러리 조성물의 APS 농도 변화에 따른 W, TiN, Oxide에 대한 연마율을 나타내는 그래프이다. Figure 8 is a graph showing the polishing rate for W, TiN, Oxide according to the APS concentration change of the CMP slurry composition according to the embodiment.
도 9는 실시예에 따른 CMP 슬러리 조성물의 질산철 농도 변화에 따른 연마율을 나타내는 그래프이다. 9 is a graph showing the polishing rate according to the iron nitrate concentration change of the CMP slurry composition according to the embodiment.
이하 본 발명을 실시예에 의하여 보다 상세히 설명한다. 그러나, 본 발명이 실시예에 의하여 한정되는 것은 아니다. Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited by the examples.
본 발명에 따른 텅스텐 연마용 CMP 슬러리 조성물은 연마제와 연마촉진제를 포함하며, 이때 연마제는 초순수에 분산된 콜로이드 실리카를 포함하고, 상기 연마촉진제는 과산화수소수, 암모늄퍼설페이트 및 질산철을 포함하는 것이 특징이다. The tungsten polishing CMP slurry composition according to the present invention comprises an abrasive and an abrasive accelerator, wherein the abrasive comprises colloidal silica dispersed in ultrapure water, and the abrasive accelerator comprises hydrogen peroxide, ammonium persulfate and iron nitrate. to be.
본 발명의 일실시예에 의하면, 콜로이드 실리카의 함량은 2 ~ 4중량%인 것이 바람직하다. 콜로이드 실리카의 함량이 2 중량% 이하인 경우 연마율이 낮고, 4중량% 이상인 경우 스크래치(scratch) 발생 가능성이 높다. According to one embodiment of the present invention, the content of the colloidal silica is preferably 2 to 4% by weight. If the colloidal silica content is 2 wt% or less, the polishing rate is low, and if it is 4 wt% or more, there is a high possibility of scratching.
또한 본 발명의 다른 일실시예에 의하면, 과산화수소수의 함량은 O.5 ~ 2중량%인 것이 바람직하다. 과산화수소수의 함량이 0.5중량% 이하인 경우 텅스텐이 산화가 이루어지지 않아 연마율 감소하고, 2중량% 이상인 경우는 텅스텐 산화물이 포화(saturation)되어 2중량% 이상의 과산화수소수 농도는 의미가 없다.In addition, according to another embodiment of the present invention, the content of hydrogen peroxide water is preferably from 0.5 to 2% by weight. When the content of hydrogen peroxide is 0.5% by weight or less, tungsten is not oxidized, the polishing rate is reduced, and when it is 2% by weight or more, tungsten oxide is saturated, so the hydrogen peroxide concentration of 2% by weight or more is not significant.
또한 본 발명의 다른 일실시예에 의하면, 상기 암모늄퍼설페이트의 함량은 0.05 ~ 1중량%인 것이 바람직하다. 암모늄퍼설페이트의 양이 0.05중량% 이하인 경우에는 TiN과 W의 선택비가 유사하기 때문에 CMP 공정에 적용하기에 적합하지 않다. In addition, according to another embodiment of the present invention, the content of the ammonium persulfate is preferably 0.05 to 1% by weight. If the amount of ammonium persulfate is 0.05% by weight or less, the selectivity between TiN and W is similar, and thus not suitable for the CMP process.
또한 본 발명의 다른 일실시예에 의하면, 질산철의 함량은 O.01 ~ 0.1중량%인 것이 바람직하다. 질산철의 함량이 0.1중량% 이상인 경우 슬러리 변색이 일어나서 CMP 공정에 적용할 경우 패드 오염 등이 문제가 발생할 수 있으며, 0.01중량% 이하인 경우에는 텅스텐 연마율이 낮아서 사용하기 어렵다. In addition, according to another embodiment of the present invention, the content of iron nitrate is preferably 0.01 to 0.1% by weight. When the content of iron nitrate is more than 0.1% by weight, slurry discoloration may occur, and when the CMP process is applied, pad contamination may occur, and when the content is less than 0.01% by weight, the tungsten polishing rate is difficult to use.
또한 본 발명의 다른 일실시예에 의하면, 텅스텐과 질화티타늄의 식각 선택비가 1: 1.5 ~ 2이고, 텅스텐과 산화막의 식각 선택비가 2: 1 이상인 텅스텐 연마용 CMP 슬러리 조성물을 제공한다. In addition, according to another embodiment of the present invention, an etching selectivity of tungsten and titanium nitride is 1: 1.5 to 2, and an etching selectivity of tungsten and oxide film is 2: 1 or more to provide a tungsten polishing CMP slurry composition.
본 발명에 따른 슬러리 조성물은 질화막이 형성된 텅스텐에 적용되므로 텅스텐과 질화티타늄의 식각 선택비가 1:1.5 이하 또는 1:2 이상인 경우와, 텅스텐과 산화막의 식각 선택비가 2:1 이하인 경우 텅스텐 플러그에 디펙트 등이 발생하게 된다.Since the slurry composition according to the present invention is applied to tungsten on which a nitride film is formed, the tungsten plug is attached to the tungsten plug when the etching selectivity of tungsten and titanium nitride is 1: 1.5 or less or 1: 2 or more, and the etching selectivity of tungsten and oxide film is 2: 1 or less. The effect is generated.
또한 본 발명의 다른 일실시예에 의하면, 조성물의 pH는 2 ~ 4 인 것이 바람직하다. pH2 이하인 경우, 강산으로 취급이 어렵고 위험하며, pH4 이상의 경우 텅스텐 산화물 형성에 의한 연마가 아닌 부식(corrosion)에 의한 연마로 인해 표면에 피트(corrosion pit)가 생긴다.In addition, according to another embodiment of the present invention, the pH of the composition is preferably 2-4. If the pH is less than 2, it is difficult and dangerous to handle with a strong acid, and if the pH is higher than 4, corrosion pit is formed on the surface due to polishing by corrosion rather than polishing by tungsten oxide formation.
이하, 바람직한 실시예를 들어 본 발명을 더욱 상세하게 설명하지만, 이는 발명의 이해를 돕기 위해 예시적으로 제시되는 것으로서, 본 발명의 범위가 이에 한정되는 것은 아니다. Hereinafter, the present invention will be described in more detail with reference to preferred embodiments, which are presented by way of example in order to help understanding of the present invention, but the scope of the present invention is not limited thereto.
실리콘 웨이퍼 위에 산화막과 질화 티타늄을 각각 증착 후 6000 Å 텅스텐을 증착한 텅스텐 웨이퍼, 실리콘 웨이퍼 위에 산화막 1000 Å 증착 후 질화 티타늄 3000 Å 증착한 질화 티타늄 웨이퍼와 절연막으로 PETEOS로 7000 Å 증착한 실리콘 산화막 웨이퍼를 사용하였다. 연마 장비로는 G&P Tech 회사의 poli-300 장비를 사용하였고, 연마 패드로는 Rohm & Haas의 IC 1000/Suba IV CMP 패드를 사용하였다. 연마 조건으로는 하강압력 2.5 psi, 정반(Table)과 스핀들(Spindle)의 속도는 모두 90 rpm, 슬러리의 유속은 100 mL/min으로 텅스텐, 질화티타늄, 실리콘막을 각각 60, 30 그리고 60 s씩 연마 하였다. Tungsten wafer deposited 6000 Å tungsten after deposition of oxide film and titanium nitride on silicon wafer, Titanium nitride wafer deposited after 1000 산화 oxide oxide on silicon wafer and titanium nitride 3000 Å deposited silicon oxide wafer Used. As a polishing machine, G & P Tech company's poli-300 machine was used, and as the polishing pad, Rohm & Haas's IC 1000 / Suba IV CMP pad was used. Grinding conditions include a down pressure of 2.5 psi, table and spindle speeds of 90 rpm, and slurry flow rates of 100 mL / min, polishing tungsten, titanium nitride, and silicon films at 60, 30, and 60 s, respectively. It was.
연마 입자로는 1차 입경이 75 nm이고 2차 입경이 215 nm인 콜로이드 실리카(Fuso, PL-7)를 4중량%를 사용하였고, 이는 초순수에 고르게 분산 되였다. 산화제로는 과산화수소수(JunSei)를 1중량%를 사용하였고, 산화 촉진제로 질산철(Ⅲ)(Sigma-Aldrich) 그리고 식각 선택비를 향상시키기 위하여 암모늄퍼설페이트(Sigma-Aldrich)를 사용하였다. 슬러리의 pH는 2 내지 3이였다.As abrasive particles, colloidal silica (Fuso, PL-7) having a primary particle size of 75 nm and a secondary particle size of 215 nm was used in 4 wt%, which was evenly dispersed in ultrapure water. 1% by weight of hydrogen peroxide (JunSei) was used as the oxidizing agent, and iron (III) nitrate (Sigma-Aldrich) was used as an oxidation promoter, and ammonium persulfate (Sigma-Aldrich) was used to improve the etching selectivity. The pH of the slurry was 2-3.
비교예 1: 과산화수소수만 포함하는 CMP 슬러리 조성물Comparative Example 1: CMP Slurry Composition Containing Hydrogen Peroxide Only
하기 표 1에 따라 CMP 공정에서 일반적으로 사용하는 H2O2 2중량% 만 첨가한 슬러리의 경우를 비교예 1로 하였으며, 도 2에 비교예 1의 슬러리 조성물의 W, TiN, Oxide에 대한 연마율을 나타내었다. According to Table 1, Comparative Example 1 was used as a slurry to which only 2% by weight of H 2 O 2 generally used in a CMP process was used. In FIG. 2, polishing of W, TiN, and Oxide of the slurry composition of Comparative Example 1 was performed. The rate is shown.
도 2에서 확인할 수 있는 바와 같이 CMP 공정에서 일반적으로 사용하는 H2O2 2중량%만 첨가한 비교예 1의 슬러리 조성물의 경우 텅스텐의 연마율은 매우 낮았다. 따라서 다른 첨가제가 필요하다는 것을 알 수 있었다. As can be seen in Figure 2 in the slurry composition of Comparative Example 1 to which only 2% by weight of H 2 O 2 commonly used in the CMP process, the polishing rate of tungsten was very low. Therefore, it was found that other additives are needed.
표 1
연마제 타입 연마촉진제
산화제(1)
콜로이드 실리카(PL-7) 4중량% H2O2 2중량%
Table 1
Abrasive type Polishing accelerator
Oxidizing agent (1)
4% by weight of colloidal silica (PL-7) 2 % by weight of H 2 O 2
비교예 2: 암모늄퍼설페이트와 과산화수소수를 포함하는 CMP 슬러리 조성물Comparative Example 2: CMP Slurry Composition Comprising Ammonium Persulfate and Hydrogen Peroxide
금속 CMP 공정에서 사용하는 암모늄퍼설페이트(APS: ammonium persulfate) 2 중량%만 첨가한 경우를 하기 표 2에서와 같은 조성을 비교예 2로 하여 W, TiN, Oxide에 대한 연마율을 측정하였으며, 그 결과를 도 3에 나타내었다. When only 2% by weight of ammonium persulfate (APS) used in the metal CMP process was added, the polishing rate for W, TiN, and Oxide was measured using the composition shown in Table 2 as Comparative Example 2. Is shown in FIG. 3.
하기 표 2에서와 같이 APS와 H2O2를 혼합한 비교예 2의 경우, 도 3에서 확인할 수 있는 바와 같이 텅스텐 연마율이 낮게 나타났다. 그러나 TiN 연마율은 향상되었다. 이에 따라 텅스텐 연마율을 향상시킬 수 있는 다른 첨가제가 필요하다는 것을 알 수 있었다.As shown in Table 2, in Comparative Example 2 in which APS and H 2 O 2 were mixed, the tungsten polishing rate was low as shown in FIG. 3. However, the TiN removal rate was improved. Accordingly, it was found that other additives capable of improving tungsten polishing rate were needed.
표 2
연마제 타입 연마촉진제
산화제(1) 산화제(2)
콜로이드 실리카(PL-7) 4중량% APS 2중량% H2O2 2중량%
TABLE 2
Abrasive type Polishing accelerator
Oxidizing agent (1) Oxidizing agent (2)
4% by weight of colloidal silica (PL-7) APS 2% by weight 2 % by weight of H 2 O 2
비교예 3: 질산철을 포함하는 CMP 슬러리 조성물Comparative Example 3: CMP Slurry Composition Comprising Iron Nitrate
하기 표 3에 따라 슬러리 조성물에 Fe(NO3)3 2중량% 를 첨가한 경우를 비교예 3으로 하여 W, TiN, Oxide에 대한 연마율을 측정한 결과, 도 4에서 보는 바와 같이 텅스텐 연마율이 1600Å/min 정도로 높게 나타났다. 그러나, 슬러리 변색에 의한 패드 오염, 수명 및 금속 오염 등의 문제가 발생하였다. As a result of measuring the polishing rate for W, TiN, and Oxide as Comparative Example 3, when 2% by weight of Fe (NO 3 ) 3 was added to the slurry composition according to Table 3, the tungsten polishing rate was shown in FIG. 4. It was as high as 1600Å / min. However, problems such as pad contamination, lifetime, and metal contamination due to slurry discoloration have occurred.
표 3
연마제 타입 연마촉진제
산화제(1)
콜로이드 실리카(PL-7) 4중량% Fe(NO3)3 2중량%
TABLE 3
Abrasive type Polishing accelerator
Oxidizing agent (1)
4% by weight of colloidal silica (PL-7) Fe (NO 3 ) 3 2 wt%
이에 따라 Fe(NO3)3 의 첨가 농도를 변화시켜 슬러리의 변색 지점을 찾았으며, 그 결과 도 5에서 확인할 수 있는 바와 같이, Fe(NO3)3 0.1 중량% 이상 첨가시 색이 조금씩 변해가기 시작했다. Accordingly, the discoloration point of the slurry was found by changing the concentration of Fe (NO 3 ) 3. As a result, as shown in FIG. 5, when the Fe (NO 3 ) 3 0.1 wt% or more is added, the color gradually changes. it started.
따라서 질산철은 0.1 중량% 이하에서 사용하는 것이 바람직하다고 확인하였다.Therefore, it was confirmed that it is preferable to use iron nitrate at 0.1 weight% or less.
비교예 4: 질산철과 암모늄퍼설페이트를 포함하는 CMP 슬러리 조성물Comparative Example 4: CMP Slurry Composition Comprising Iron Nitrate and Ammonium Persulfate
하기 표 4에서와 같이, H2O2는 제외하고 Fe(NO3)3 0.01 중량%와 APS 농도를 변화시킨 경우를 비교예 4로 하여 W, TiN, Oxide에 대한 연마율을 측정한 결과, 도 6의 결과와 같이 텅스텐의 연마율은 매우 낮게 나타났다. As shown in Table 4 below, the polishing rate for W, TiN, and Oxide was measured as Comparative Example 4, except that 0.01 wt% of Fe (NO 3 ) 3 and APS concentration were excluded except for H 2 O 2 . As shown in FIG. 6, the removal rate of tungsten was very low.
표 4
연마제 타입 연마촉진제
산화제(1) 산화제(2)
콜로이드 실리카(PL-7) 4중량% Fe(NO3)3 0.01중량% APS 0 ~ 0.05중량%
Table 4
Abrasive type Polishing accelerator
Oxidizing agent (1) Oxidizing agent (2)
4% by weight of colloidal silica (PL-7) Fe (NO 3 ) 3 0.01% by weight APS 0 ~ 0.05% by weight
비교예 5: 과산화수소수와 질산철을 포함하는 CMP 슬러리 조성물 Comparative Example 5: CMP Slurry Composition Comprising Hydrogen Peroxide and Iron Nitrate
하기 표 5에서와 같이 H2O2 1중량%에 Fe(NO3)3 농도를 변화시킨 경우를 비교예 5로 하여 W, TiN, Oxide에 대한 연마율을 측정하였으며, 그 결과를 도 7에 나타내었다.As shown in Table 5, the polishing rate for W, TiN, and Oxide was measured using Comparative Example 5 when the Fe (NO 3 ) 3 concentration was changed to 1% by weight of H 2 O 2 , and the results are shown in FIG. 7. Indicated.
표 5
연마제 타입 연마촉진제
산화제(1) 산화제(2)
콜로이드 실리카(PL-7) 4중량% H2O2 1중량% Fe(NO3)3 0.01~ 1중량%
Table 5
Abrasive type Polishing accelerator
Oxidizing agent (1) Oxidizing agent (2)
4% by weight of colloidal silica (PL-7) 1% by weight of H 2 O 2 Fe (NO 3 ) 3 0.01 ~ 1 wt%
텅스텐의 경우 Fe(NO3)3 농도가 0에서 0.03중량%까지 증가함에 따라 750 에서 1150 Å/min까지 연마율이 급격하게 증가하였으며 0.03에서 1중량%까지 농도가 증가함에 따라 1150에서 1830 Å/min까지 연마율이 조금씩 증가하였다. For tungsten, the polishing rate increased sharply from 750 to 1150 Å / min as the Fe (NO 3 ) 3 concentration increased from 0 to 0.03% by weight, and 1150 to 1830 Å / min as the concentration increased from 0.03 to 1% by weight. The polishing rate increased little by little.
TiN의 경우는 0에서 0.03중량%까지 Fe(NO3)3 농도가 증가함에 따라 연마율이 1630에서 2580 Å/min 까지 급격하게 증가하다가 0.03중량%이상으로 농도를 증가 시키면 2580 Å/min에서 점점 연마율이 감소하여 Fe(NO3)3 1중량%에서 2030 Å/min까지 연마율이 감소하였다. In the case of TiN, as the Fe (NO 3 ) 3 concentration increased from 0 to 0.03% by weight, the polishing rate increased rapidly from 1630 to 2580 Å / min, and then increased from 2580 Å / min when the concentration was increased above 0.03% by weight. The polishing rate decreased so that the polishing rate decreased from 1% by weight of Fe (NO 3 ) 3 to 2030 dl / min.
Oxide의 경우 Fe(NO3)3 의 농도에 따라 식각 속도의 큰 변화가 없이 500에서 600 Å/min 정도의 연마율을 보여주었다. Oxide showed a removal rate of 500 to 600 Å / min without significant change in the etching rate according to the Fe (NO 3 ) 3 concentration.
실시예 1: 과산화수소수, 질산철, 암모늄퍼설페이트를 포함하는 CMP 슬러리 조성물Example 1 CMP Slurry Composition Comprising Hydrogen Peroxide, Iron Nitrate, Ammonium Persulfate
상기 실험 결과, 텅스텐 CMP 동안에 TiN-W의 식각 선택비는 1.5에서 2 이상이 필요하며 W-Oxide의 식각 선택비의 경우는 2이상의 선택비가 필수적으로 필요하다는 것을 알 수 있었다. As a result of the experiment, it was found that the etching selectivity of TiN-W during tungsten CMP needs 1.5 to 2 or more, and the etching selectivity of W-Oxide is necessary to select 2 or more.
또한 산성영역에서 콜로이달 실리카, H2O2 그리고 Fe(NO3)3을 사용하는 현재 슬러리로는 슬러리의 변색 문제와 TiN-W, W-Oxide의 식각 선택비의 문제들을 해결할 수 없다는 결론을 얻었다. 실험 결과, 0.03중량% 이하의 Fe(NO3)3 농도에서는 W과 TiN의 연마율이 모두 급격히 증가하기 때문에 슬러리의 변색이 되지는 않지만 사용이 어렵다는 것을 알 수 있었다. In addition, it is concluded that the current slurry using colloidal silica, H 2 O 2 and Fe (NO 3 ) 3 in the acidic region cannot solve the problem of discoloration of the slurry and the problems of etching selectivity of TiN-W and W-Oxide. Got it. As a result, it was found that at the Fe (NO 3 ) 3 concentration of 0.03% by weight or less, the polishing rate of W and TiN increased rapidly, so that the slurry was not discolored, but it was difficult to use.
따라서 질화 티타늄 연마율을 감소시키며 변색이 되지 않는 새로운 첨가제와 새로운 슬러리 개발의 필요성에 따라 하기 표 6의 조성을 갖는 슬러리 조성물을 제조하였다. Therefore, a slurry composition having a composition of Table 6 was prepared according to the necessity of developing a new slurry and a new slurry that would not discolor and reduce the titanium nitride removal rate.
표 6
연마제 타입 연마촉진제
산화제(1) 산화제(2) 산화제(3)
콜로이드 시리카(PL-7) 4중량% H2O2 1중량% Fe(NO3)3 0.05중량% APS 0 ~ 5중량%
Table 6
Abrasive type Polishing accelerator
Oxidizing agent (1) Oxidizing agent (2) Oxidizing agent (3)
4% by weight of colloidal silica (PL-7) 1% by weight of H 2 O 2 Fe (NO 3 ) 3 0.05% by weight APS 0 ~ 5% by weight
TiN의 경우 Fe(NO3)3 0.05중량%일 때, 0 ~ 0.1중량%까지 APS 농도가 증가함에 따라 2350에서 1900 Å/min 까지 연마율이 급격하게 감소하고, 0.1에서 1중량%까지 농도가 증가함에 따라 1900에서 1530 Å/min 까지 연마율이 조금씩 감소하는 반면, 텅스텐 연마율은 APS 농도가 0에서 0.1 중량%까지 증가함에 따라 1060에서 1270 Å/min 까지 급격하게 증가하다가 0.1에서 1 중량%까지 1270에서 1300 Å/min 으로 연마율이 조금씩 증가하는 경향을 나타내었다. 이러한 결과는 APS를 첨가함으로써 TiN의 연마율은 억제를 시키며 텅스텐의 연마율은 향상 시킴으로 TiN-W과 W-Oxide의 식각 선택비를 적절히 조절할 수 있다는 것을 확인하였다.(도 8)In the case of TiN, when Fe (NO 3 ) 3 0.05% by weight, as the APS concentration increased from 0 to 0.1% by weight, the polishing rate decreased drastically from 2350 to 1900 Å / min, and the concentration was increased from 0.1 to 1% by weight. As it increases, the polishing rate gradually decreases from 1900 to 1530 Å / min, while the tungsten polishing rate increases rapidly from 1060 to 1270 Å / min as the APS concentration increases from 0 to 0.1% by weight and then from 0.1 to 1% by weight. Until 1270 to 1300 Å / min showed a slight increase in the polishing rate. These results confirmed that by adding APS, the polishing rate of TiN was suppressed and the polishing rate of tungsten was improved so that the etching selectivity of TiN-W and W-Oxide could be properly adjusted. (FIG. 8)
콜로이드 실리카 기반의 슬러리에 H2O2 1중량%, APS를 첨가하지 않은 것과 0.05 중량%를 첨가한 슬러리에 Fe(NO3)3 농도에 따라 연마 평가 결과 TiN은 약 600 Å/min 정도 연마율이 감소한 반면 W과 Oxide의 연마율은 거의 변화가 없었다. 결과적으로 APS 0.05 중량%와 Fe(NO3)3 0.1중량%에서 TiN-W 그리고 W-Oxide의 식각 선택비는 1.8 : 1과 2.1 : 1을 각각 달성했다.(도 9)In the slurry of colloidal silica-based slurry, 1% by weight of H 2 O 2 , no APS and 0.05% by weight of Fe (NO 3 ) 3 were evaluated according to the Fe (NO 3 ) 3 concentration. While this decrease, the removal rate of W and oxide remained almost unchanged. As a result, 0.05 wt% APS and Fe (NO 3) 3 eseo 0.1 wt% TiN-W and W-Oxide etch selectivity of the ratio 1.8: 1, respectively was achieved (Fig. 9): 1 and 2.1.

Claims (5)

  1. 연마제와 연마촉진제를 포함하는 텅스텐 연마용 CMP 슬러리 조성물로서, A tungsten polishing CMP slurry composition comprising an abrasive and an abrasive promoter,
    상기 연마제는 초순수에 분산된 콜로이드 실리카를 포함하며, The abrasive includes colloidal silica dispersed in ultrapure water,
    상기 연마촉진제는 과산화수소수 0.5 ~ 2 중량%, 암모늄퍼설페이트 0.05 ~ 1중량% 및 질산철 O.O1 ~ 0.1중량% 을 포함하는 텅스텐 연마용 CMP 슬러리 조성물.The polishing accelerator CMP slurry composition for tungsten polishing comprising 0.5 to 2% by weight of hydrogen peroxide, 0.05 to 1% by weight of ammonium persulfate and 0.1 to 0.1% by weight of iron nitrate.
  2. 제1항에 있어서, The method of claim 1,
    상기 콜로이드 실리카의 함량은 2 ~ 4 중량%인 것을 특징으로 하는 텅스텐 연마용 CMP 슬러리 조성물.Tungsten polishing CMP slurry composition, characterized in that the content of the colloidal silica is 2 to 4% by weight.
  3. 제1항에 있어서, The method of claim 1,
    텅스텐과 질화티타늄의 식각 선택비가 1: 1.5 ~ 2인 것을 특징으로 하는 텅스텐 연마용 CMP 슬러리 조성물.Tungsten and titanium nitride etch selectivity ratio of 1: 1.5 ~ 2 tungsten polishing CMP slurry composition characterized in that.
  4. 제1항에 있어서, The method of claim 1,
    텅스텐과 산화막의 식각 선택비가 2: 1 이상인 것을 특징으로 하는 텅스텐 연마용 CMP 슬러리 조성물.Tungsten and CMP slurry composition for tungsten oxide, characterized in that the etching selectivity of the oxide film is 2: 1 or more.
  5. 제1항에 있어서, The method of claim 1,
    상기 조성물의 pH는 2 ~ 4 인 것을 특징으로 하는 텅스텐 연마용 CMP 슬러리 조성물.PH of the composition is tungsten polishing CMP slurry composition, characterized in that 2 to 4.
PCT/KR2012/005397 2011-08-16 2012-07-06 Cmp slurry composition for tungsten polishing WO2013024971A2 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20040086290A (en) * 2002-01-24 2004-10-08 로델 홀딩스 인코포레이티드 Tungsten polishing solution
KR20050071139A (en) * 2003-12-31 2005-07-07 동부아남반도체 주식회사 Method for fabricating tungsten plug of semiconductor device
KR20080003260A (en) * 2006-06-30 2008-01-07 주식회사 엘지화학 Chemical mechanical polishing slurry
KR20080028790A (en) * 2006-09-27 2008-04-01 테크노세미켐 주식회사 A slurry composition for forming tungsten line and method for manufacturing semiconductor device using the same
KR20110063400A (en) * 1996-11-26 2011-06-10 캐보트 마이크로일렉트로닉스 코포레이션 A composition and slurry useful for metal cmp

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Publication number Priority date Publication date Assignee Title
KR20110063400A (en) * 1996-11-26 2011-06-10 캐보트 마이크로일렉트로닉스 코포레이션 A composition and slurry useful for metal cmp
KR20040086290A (en) * 2002-01-24 2004-10-08 로델 홀딩스 인코포레이티드 Tungsten polishing solution
KR20050071139A (en) * 2003-12-31 2005-07-07 동부아남반도체 주식회사 Method for fabricating tungsten plug of semiconductor device
KR20080003260A (en) * 2006-06-30 2008-01-07 주식회사 엘지화학 Chemical mechanical polishing slurry
KR20080028790A (en) * 2006-09-27 2008-04-01 테크노세미켐 주식회사 A slurry composition for forming tungsten line and method for manufacturing semiconductor device using the same

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