TW200408701A - Slurry for mechanical polishing (cmp) of metals and use thereof - Google Patents

Abstract

Slurry compositions comprising an oxidizing agent, optionally a copper corrosion inhibitor, abrasive particles; surface active agent, a service of chloride and a source of sulfate ions.

Description

200408701

1. [Technical field to which the invention belongs] 1. The present invention relates to a composition of a polishing liquid used for polishing or planarizing a surface 'especially for integrated circuit equipment using copper as interconnect wiring' such as In a semiconductor wafer having the characteristics of damascene or dual damascene, copper is ground or planarized; related polishing steps using the polishing liquid of the present invention are also included in the present invention. I. [Previous Technology] 〶In the microelectronic component industry, in the process of manufacturing integrated circuits, grinding scratch-free surfaces and / or removing excess materials to achieve planarization The polishing method includes chemical mechanical polishing. For example, metals such as aluminum, copper, and tungsten can be planarized by chemical mechanical polishing. Furthermore, refractory metal uner, typically under aluminum, copper, or tungsten, has excellent adhesion to the insulator and has a good contact resistance with the driver for low-order metal conductors. resistance). Typical gaskets include niobium, buttons, tungsten and titanium or a combination of nitrides, oxides and / or oxynitrides or other refractory metals. Recently, copper and copper alloys have been developed as wafer interconnects / circuit materials, especially for semiconductor wafers of very large scale integrated circuits (VLS I) and ultra large scale integrated circuits (ULSI). Compared with aluminum and aluminum alloy, using copper and copper alloy can improve device performance

Page 9 200408701 V. Description of the Invention (2) (device performance) 〇

During the manufacture of semiconductor devices, metal interconnect materials such as copper and copper alloys of circuit structures begin to cover the surface of the dielectric layer that has been etched with blanket1: electrodeposited film. . Copper is deposited to fill pre-etched indentations or trenches (p r e-e t c h e d), leaving too much metal that must be removed. Once the metal is removed, a silver wire remains on the surface of the wafer. This process is called metal inlay. The general chemical mechanical polishing includes a circular or channel device, a polishing pad is in contact with the wafer, the down pressure is controlled and a suitable polishing liquid is provided. In this method, too much metal can be removed, and the surface of the wafer can be planarized again (replanarization). Recently, grinding mills with appropriate abrasive particles have been used in chemical mechanical grinding. For a detailed description of chemical mechanical polishing, see us

Patent Nos. 4,671,851, 4,910,155 and 4,94 ° 4/83 6, this section has been incorporated for reference purposes.

It is typically used for chemical mechanical polishing of metals. Its polishing solution is a liquid suspension containing a metal oxidized abrasive such as alumina, S1llca, organic acid, and interfacial activity μ. (smrfactant), chelate and appropriate oxidation (oxdizUg agent). The abrasive moves material through mechanical action, while the oxidant aids mechanical removal by dissolving. The oxidizing agent for general commercial use or patented grinding fluid is an inorganic metal salt, such as iron nitrate (Fe (rib,

200408701 V. Description of the invention (3) 3) or acetic acid (KI03) and a certain concentration of ammonia persulfate and hydrogen peroxide. The purpose of using the complex compound and the admixture is to prevent the formation of free copper ions in the polishing liquid which causes discoloration of the polishing pad and increase of the oxidant reactivity. When performing chemical mechanical grinding, the addition of additives can improve the grinding performance of the grinding fluid. One need to consider is that in the current chemical mechanical polishing technology of copper, the polishing liquid can generally provide a polishing rate of 2000 to 500 angstroms per minute. For examples, see US patents 5,954,997, 6, 1 1 7, 775 and 6, 1 2 6,853. Dang Zeng

Increasing the mechanical parameters' as follows: Increasing the pressure to 6 pieces per square inch (p s 丨) can increase the grinding rate to 150 to 170 angstroms / minute. However, even at this speed, when applied to the Back End Of the Line, a long grinding time is required to remove the 1-2 micron copper. Furthermore, when patterned wafers are ground, the increase in the down force will cause copper dishing, so the increase in the down force should be avoided. Therefore, it is expected that a set of grinding procedures can overcome the problems of dishing and erosion caused by grinding copper. In addition, because the copper surface is relatively soft (so f t), the grinding process must avoid scratching the copper surface, and the polishing liquid used must be highly selective for copper and any gasket materials that come into contact with copper. Furthermore, a detailed description of selective grinding and chemical mechanical grinding in the known art can be found in US 5,676,587 to Undeu at al 'Select.ve P0llsh Pr〇cess f Ur T Uan,, ^

Page 11 200408701 V. Description of the invention (4) Nitride, Tantalum Nitride This section has been incorporated as a reference. [Summary of the invention] The present invention provides a composition for a grinding fluid, which can be used at a downforce of not more than 6 lbs / At a square inch, the grinding rate is significantly increased by at least 8000 to 90 Angstroms / minute. Therefore, the composition provided by the present invention significantly reduces the grinding time. This document provides a minimum of copper recession and oxygen abrasion during the grinding process. Furthermore, the polishing liquid provided by the present invention is selective for polishing copper, tantalum, and nitride; and one of 24, one of titanium, tungsten, and / or a compound thereof, and other gasket materials. In particular, the present invention relates to an abrasive liquid, including abrasive particles, an oxidizing agent, a chloride ion source (kciHoride ion source), and a sulfate ion source. The source ion also relates to grinding a surface, including shaking The polishing liquid is used to polish the surface, and the surface is used in contact with the polishing pad.

By referring to the following description, those skilled in the art and other items of the present invention will be described with the most simplified but best embodiment to describe the present invention. The invention includes other different embodiments and all of them. It will be easier to understand. The following description is to understand the changes and changes. The above

200408701 Fifth, the description of invention description (5) is only for illustration and not limitation. Fourth, [implementation]

The polishing liquid composition in the present invention includes an oxidant. Suitable oxidants include: ο X idizingmeta 1 sa 11 s, oxidizing metal complex, such as hydrochloric acid, persulfuric acid, peracetic acid, peracid (Oxidizing acid) of periodic acid, such as iron salt containing nitrate and sulfate, potassium ferricyanide λ peroxy ^ [hydrogen peroxide, aluminum salt , Sodium salt, potassium salt such as potassium iodate (potassiU [n iodate), ammonium salt such as ammoniuin cerium nitrate, phosphate salt, chloride, perchlorate Such as sodium perchlorate, nitrate, permanganate, such as potassium permanganate, persulfate and a mixture of the above components. 0 The preferred oxidant is ferric nitrate and peroxidation.

hydrogen. The typical content of the oxidant is about 50 grams / liter, and the preferred content is about 0 ~ 40 grams / liter. The ingredients of the composition of the present invention used for grinding copper (copper corrosion inhibitor) also contain a copper corrosion inhibitor. When deducting the scorpion, it is a typical steel corrosion inhibitor.

Page 13 20030701 Description of the invention (6) Contains imidazo (eid), triazole (such as 1,2,4-triazole (1,2,4 triazole) and phenyl azide (benz〇1: riaz 〇le). Copper rot inhibitor contains Rio 0.1 to 5 g / L, typical example is about 2.5 G / L. The mill of the present invention is often made of a mixture of aluminum, cer ia, and two, including compounds on the earth The suspended state exists. Applicable for rare valence (Tb4 +) coupling agent. Substances A, A, and A also include abrasive particles, and the types thereof include abrasive particles currently used in abrasive liquids. Suitable embodiments include oxygen, iron oxide, zirconia, titanium dioxide, and titanium dioxide. The preferred component is alumina. The abrasive particles can also be some duaiialent ions or their colloidal hydroxide ^ f. Rare ions on the earth are fields with higher valence. Examples of m are tetravalent europium (c e4 +), tetravalent europium (pr4 +), a suspension of tetra- or vicinal oxidants, such as oxide bromide. The rare colloidal oxidant on the earth or on the earth can be used as a oxidative aPPli: titn rare S additive. It has been disclosed in US patent ppiication Serial Number ns / 7u ^ For reference, open 08/7 56,36 1. The full text has been incorporated into J as part of the grinding slurry. Typical grinding & r λ shell size is between about 10 to 1 0 0 0 nanometer (nanometer) and the amount of the six clubs is about 0.5% ~ 6 / will 1 the size is between 50_2 0 0 nm. The typical content is °, and the content of Che Fu Jia is about 2% ~ 4% by weight.

B Page 14 200408701 V. Description of the invention (7) Good products are necessary ^ 'A mixture of the above-mentioned abrasive particles can be used, for example, the mixture contains alumina, silica, and zirconia, wherein the ratio of alumina is about 0 1% to 6% by weight, the proportion of silica is between 0.1% to 5% by weight, and the proportion of oxidized oxide is between 0.1% and 6% by weight. A typical mixing ratio is about 1% to 5% by weight of alumina and about 1% to 20% of silica. The present invention is preferably an abrasive in the form of an aqueous solution. Other suitable abrasives include the use of dilute organic solvents such as propylene carbonate, monohydric and polyhydric alcohols such as Alcohol, ethanol, ethylene glycol and glycerol. Of course, a mixed solution of the above solvents or a mixed solution of water may be used in the abrasive.

The composition of the present invention also contains a surfactant. Suitable surfactants include anionic, cat ionic, nonionic, and zwitterionic compounds. Some examples of surfactants used in the present invention have been disclosed in, for example, Kirk-01 her, Encyclopedia of Chemistry Terminology, 3rd Edition, Vol. 22 (John Wiley & Sons, 1983); Sislet & Wood, Encyclopedia of Surface Active Agents (Chemical Publishing Co., Inc. 1 9 6 4); McCutcheon's

Emulsifiers & Detergents, North American and International Edition (McCutcheon Division, The MC

Page 15 200408701 V. Description of Invention (8)

Publishing Co., 1991); Ash, The Condensed

Encyclopedia of Surfactants (Chemical Polishing Co., Inc., 1989); Ash, What Every Chemical Technologist Wants to Know Abou t " · Ειηι 1 s i f i er s and Wetting agents, Vo 1. 1 (Chemi ca 1 Polishing Co.,

Inc., 1988); Tadros, Surfactants (Academic Press, 1984); Napper, Polymeric Stabilization of Colloidal Dispersion (Academic Press, 1 9 8 3); Rosen,

Surfactant & Interfacial Phenomena, 2nd Edition (John Wiley & Sons, 1989). The above-mentioned embodiments have been incorporated by reference. Suitable examples of surfactants are Na-alkyl sulfate, Na-alkyl sulfonates, tet ramethy 1 ammonium halides, hexadecyl halide Trimethyl ammonium halides, hydroxides, nonyl ether and a mixture of the above compounds. Preferred examples of the surfactant are sodium sulfate compounds containing hexyl, hyptyl, octyl, nonyl and lauryl (1 aury 1), the most preferred of which is pentyl Potassium sulphate (Na octyl sulfate). Effective in commercial designs of Dupanol 80 (Witco), Standapol LF (Henke 1 / Cogn is), Texapon842 (Henke 1), Texapon 890 (Henkel) s \ Su1fotex 0A (Henkel) and Polystep B-29 (Stephan) The surfactant is ammonium sulfate.

Page 16 200408701

V. Description of the invention (9) A typical surfactant content is about 0 · b; [00 ml / litre, and the comparative content is about 20-50 ml / litre. X & 4s also includes chloride ion source and sulfate ion source. Chloride and sulfate ion sources typically exist in the form of salts, including alkali metals (such as sodium and potassium), and alkaline earth metals (such as words, and salts). . The preferred source of gas ions is sodiuin chloride, and the more preferred source of sulfate ions is sodium sulfate. The chloride ion source and the sulfate ion source typically have a content of about 0.001 to 5 g / liter. The content of a preferred gas ion source is about 0.05 to 0.5 g / liter; and the content of a sulfate ion source is about 1 to 3 g / liter. The two parts, soil and B, have a sulfate ion source that is not necessary, but the composition of the preferred grinding fluid includes A. A includes oxidant, surfactant, gas ion source, and corrosion inhibitor (if B is included, it contains abrasive particles.

• When using the present invention, especially when combined with the appropriate concentration, it has the following advantages: Yes. A large copper polishing rate can be obtained at a small downforce (polish rat =, for abrasive steel and other gasket materials such as tantalum When it is used with titanium, it has good selectivity. After cleaning, the surface is relatively clean; the final transfer pattern is relatively complete & 'the car has fewer metallurgical defects, such as scratches,

Page 17, 200408701 V. Description of the invention (ί) Depression or similar defects The present invention can be used for grinding steel, tungsten, aluminum and other alloys containing the above metals, and for grinding copper, tungsten, aluminum and other materials, such as titanium, nitride The titanium, tantalum and nitride groups are remotely selectable. The structure obtained according to the present invention is the same as that of a typical semiconductor device, and includes copper interconnects (lines, plugs, vias, and local interconnects) buried in a dielectric material such as silicon dioxide (dielectric material). ) And the capply layer (capp i ng l ^ yer) such as si 1 i con nitri de 'is just like the structure of the low dielectric (10wk) metal damascene method or the two-channel metal damascene method. The typical silicon dioxide is deposited by high density plasma method (silicon dioxide or tetraethylorthosilicate). Typical copper interconnects use groups, nitride buttons, titanium, titanium nitride, or combinations thereof as a barrier or liner material between copper and the dielectric layer '. 'As such, the CMP composition is in contact with a variety of materials, such as copper, a dielectric or cover layer, and the backside of a wafer, which is typically a thin layer of silicon oxide. Furthermore, the abrasive composition must be selective to the metal and dielectric layer to be removed. An example of the high speed of grinding copper that can be studied at a rapid rate

Page 200408701 V. Description of the invention (11) If 'the down pressure is used, it can be as small as about 1 fragment per square inch. The typical pressure is about 1 pound per square inch, preferably 2 to 6 pounds per square inch. The parameters of other grinding or flattening techniques can be familiar with this item. For example, when performing grinding day, the typical rotation speed of the polishing pad is about 1 minute; (1), (rpm), preferably about 40 ~ 80 times per minute; u: 4 1 ~ 90 times 10 to 70 times per minute, preferably about 15 to 60 times per minute. The grinding mill may be an object currently known for grinding into a microelectronic element. The polishing rate obtained by using the present invention is about 6,000 to 100,000. The preferred polishing rate can reach 8000-9000 Angstroms / minute. Gadolinium / Brazil 'The following non-limiting examples are provided to further illustrate the present invention. Table 1 shows the grinding rate of copper under different or lacking salts: the copper grinding rate is reduced to 330 angstroms / minute; however, ^ 00f / sodium chloride (mM) sodium chloride can increase the grinding rate Increase to about = 2 and again :. Adding Dupono1 ′ can also increase the copper polishing rate to about H ·? =: 1 11 ·, where DUPON01 is an anion based on sodium octyl sulfate, although the interface is dense. And the peasant preparations post, other contributions. ’, There is no special effect on copper grinding rate

Page 19 200408701 V. Description of the invention (12) The component of the surfactant Duponol (Dupovt), Standapoll (Cognis) or Texapon (Cognis) is sodium caprylate. Table 2 shows the copper milling rate using Duponol (sodium octanoate) and other sodium salts. It is clear that, without other special effects, sulfate and chlorine can increase the copper milling rate. Table 3 shows the c⑽bined effect of chlorine and other salts. Under all conditions, the addition of chlorine can increase the milling rate of copper. Table 4 shows the addition effects of sodium chloride, sodium octanoate and other salts. Figure-shows the effect of downforce on the grinding rate of steel with different additives. = Compared with curve 1 and curve 2, even under the condition of large downforce, the addition of bta will reduce the polishing rate of copper. From curves 3, 4 and? Zhongke does not particularly increase the polishing rate of copper. However, the addition of gas has the combined effect of sodium sulfate and special ingredients. Qu ,, Quan 5 6 This shows that under the conditions of low concentration of sulphur, sulphuric acid is provided by the invention. Another example 'combines different flow rates to produce different slags: This is the best application of the invention. During grinding, at different times = control

200408701 V. Description of the invention (13) The flow rate is used to obtain different polishing liquid compositions, that is, different polishing conditions. Based on the above description of the preferred embodiment of the present invention, which should be familiar to those skilled in the art, the method of the present invention can be applied to any field to which the method is applicable, and some general equal modifications and changes Undoubtedly, it does not depart from the spirit and scope of the present invention. With the description of the preferred embodiments of the present invention, those skilled in the art will be able to understand and implement the present invention and its application changes more easily. However, the scope of the patent of the present invention cannot be limited by this. Likewise, the scope of the patent of the present invention reasonably extends to embodiments that include substitutions.

Page 21, 200408701 Brief description of the drawings V. [Simplified illustration of the diagram] Fig. 1 is a graph of the relationship between the down pressure and the polishing rate of copper under different compositions; Figs. 2 and 3 are the relations of the different compositions to the polishing rate Illustration.

Page 22

Claims (1)

200408701 6. Application patent scope 1. A kind of abrasive liquid (s 1 urry) composition, including: abrasive particles (abrasive particle); gasification agent (〇xidizer); surface active agent (surface active agent chloride ion source (chloride ion source) ); And a carbonate ion source (sulfate ion source 2) as described in the patent application of the scope of the polishing solution composition, wherein the grinding content of about 0.5 ~ 6% by weight, the oxidant content of about 1 ~ 50 grams The content of the surfactant is about 0.1 to 100 ml / liter, the content of the chloride ion source is about 0.001 to 20 g / liter, and the sulfate ion source is about 0.00 to 20 G / litre. 3 · The polishing liquid composition as described in item 1 of the patent application scope, which includes a surname inhibitor (c 〇rr 〇si ο ninhibit 〇r). 4 · as claimed in item 3 of the patent application scope The polishing liquid composition described above, wherein the content of the corrosion inhibitor is about 0: [~ 5 g / liter. 5 · The polishing liquid composition according to item 4 of the patent application scope, wherein the corrosion inhibitor Self-contained microphone laugh (i m i d billion ζ ο 1 e), three spit (t r i a ζ ο 1 e) and substituted with two groups laugh-yl (Substituted) of. 11 Page 23 200408701 6. Application scope of patent 6. The grinding fluid composition as described in item 4 of the scope of application for patent, wherein the rot inhibitor includes phenyl azide (be η ζ 〇tria ζ ο 1 e) . 7. The polishing liquid composition according to item 1 of the scope of the patent application, wherein the gas source comprises sodium chloride. 8. The polishing liquid composition according to item 1 of the scope of the patent application, wherein the content of the chlorine ion source is about 0.01 to 5 g / liter. 9. The polishing liquid composition according to item 1 of the scope of the patent application, wherein the content of the chlorine ion source is about 0.05 to 0.1 g / liter. 10. The polishing liquid composition according to item 1 of the scope of patent application, wherein the content of the sulfate ion source is about 1 to 3 g / liter. 11. The polishing liquid composition according to item 1 of the scope of the patent application, wherein the sulfate ion source comprises sodium sulfate (s d i u m s u 1 f a t e). 1 2. The polishing liquid composition according to item 1 of the scope of the patent application, wherein the oxidizing agent comprises iron shisite acid (f e r r c n i t r a t e). 1 3. The polishing liquid composition according to item 1 of the scope of the patent application, wherein the grinding particles include alumina (a 1 u m i n a). Page 24 200408701 VI. Scope of patent application 1 4. The polishing liquid composition according to item 1 of the scope of patent application, wherein the surfactant includes a sulfate. 15. The polishing liquid composition according to item 14 of the scope of the patent application, wherein the sulfate is selected from sodium hexyl sulfate, sodium heptyl sulfate, and sodium octanoate. ctyl sulfate), sodium nonyl sulfate, sodium lauryl sulfate, and mixtures thereof. 1 6. The polishing liquid composition according to item 1 of the scope of the patent application, wherein the surfactant is selected from sodium alkyl sulfate, alkyl sulfonate, and quaternary group of ammonium salt), nonyl ether and mixtures thereof 0 1 7. The polishing liquid composition as described in item 1 of the scope of patent application, wherein the surfactant comprises sodium octyl sulfate. 1 ·· A method of polishing a surface 'including providing a polishing liquid composition' whose components include: an abrasive particle; an oxidant; a surfactant; a gas ion source; Page 25 200408701 6. Scope of patent application and a sulfate ion source; and when polishing the surface, contact the surface with a polishing pad. 19 · The method according to item 18 of the scope of patent application, the surface of which is selected from the group consisting of copper, Ming, Yan and their alloys. 2 0. The method as described in item 19 of the scope of patent application, wherein the surface to be ground is copper or a copper alloy, and the grinding fluid contains a copper corrosion inhibitor ° 2 1 · as applied The method described in the patent scope item 20, wherein the refractory metal wire (refract oremeta 1 1 ine) is placed under copper or a copper alloy. 22. The method as described in item 21 of the scope of patent application, which applies that the fireproof metal wire is selected from the group of sharp, button, titanium, its nitrides, and mixtures thereof 2 3 · as the scope of patent application, item 18 In the method, the downforce when performing the grinding is about 1 to 9 psi. 2 4. The method according to item 23 of the scope of patent application, wherein the downforce during grinding is about 2 to 6 pieces / square inch. * 11 Page 26, 200408701 6. Patent application scope 2 5. The method described in item 20 of the patent application scope, wherein the polishing pad rotates at a rotation speed of about 10 to 90 times per minute (rpm) while polishing is performed, and the wafer is loaded The hourly speed is about 10 to 70 times per minute. Page 27