Slurry composition for polishing metal film, and method for polishing metal film by using same

Abstract

The present invention relates to a slurry composition for polishing a metal film, and a method for polishing a metal film by using same, the slurry composition comprising: colloidal silica polishing particles; an oxidizing agent; and a titanium nitride polishing conditioner.

Description

Slurry composition for polishing metal films and method for polishing metal films using the same

[0001] The present invention relates to a slurry composition for polishing metal films and a method for polishing metal films using the same.

[0002] Microelectronic device wafers are used to form integrated circuits. Microelectronic device wafers consist of a wafer, such as silicon, with patterned regions within the wafer for the deposition of different materials having insulating, conductive, or semiconductive properties. To achieve accurate patterning, excess material used to form layers on the wafer must be removed. Furthermore, to fabricate functional and reliable circuits, it is important to manufacture a flat or planar microelectronic wafer surface prior to subsequent processing. Therefore, it is necessary to remove and / or polish specific surfaces of the microelectronic device wafer.

[0003] Chemical Mechanical Polishing (CMP) is a process in which any material is removed from the surface of a microelectronic device wafer, and the surface is polished by combining physical processes, such as polishing, with chemical processes, such as oxidation or chelation. In its most basic form, CMP involves applying a slurry, for example, a solution of abrasives and active compounds, to a polishing pad to achieve removal, planarization, and polishing processes by buffing the surface of the microelectronic device wafer. In the fabrication of integrated circuits, the CMP slurry must also be capable of preferentially removing films containing composite layers of metals and other materials so that a highly planar surface can be produced for subsequent lithography or patterning, etching, and thin film processing.

[0004] CMP slurry compositions typically exhibit different polishing rates depending on the polishing target, and various slurry compositions capable of improving each polishing rate are developed and utilized depending on the type of polishing target. However, there is a demand for a CMP slurry composition that can improve the polishing rate and polishing selectivity for polishing target films containing titanium nitride and / or titanium, while minimizing the occurrence of secondary defects such as voids, dishing, and erosion that may occur due to polishing.

[0005] The present invention aims to provide a slurry composition for polishing metal films that can minimize the occurrence of secondary defects such as voids, dishing, and erosion while securing a polishing rate and polishing selectivity ratio for titanium nitride films.

[0006] However, the problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below.

[0007] A slurry composition for polishing a metal film according to one embodiment may include colloidal silica polishing particles; an oxidizing agent; and a titanium nitride film polishing regulator.

[0008] The particle size of the above colloidal silica abrasive particles may be 20 nm to 200 nm.

[0009] The above colloidal silica abrasive particles may be included in an amount of 0.0001% to 1% by weight relative to the total weight of the slurry composition for polishing metal films.

[0010] The above oxidizing agent may comprise at least one selected from the group consisting of hydrogen peroxide, hydrogen peroxide, urea, percarbonate, periodic acid, periodate, perchloric acid, perchlorate, perbromic acid, perbromate, perboric acid, perborate, permanganic acid, permanganate, persulfate, bromate, chlorate, hypochlorite, chromate, iodate, iodic acid, ammonium persulfate, benzoyl peroxide, calcium peroxide, barium peroxide, sodium peroxide, and urea peroxide.

[0011] The above oxidizing agent may be included in an amount of 0.05% to 4% by weight relative to the total weight of the metal film polishing slurry composition.

[0012] The above titanium nitride film polishing modifier may be an organic acid with a pKa value of -6 to 6.

[0013] The above titanium nitride film polishing modifier may comprise one or more selected from the group consisting of oxalic acid, malonic acid, citric acid, malic acid, maleic acid, formic acid, lactic acid, acetic acid, picolinic acid, succinic acid, tartaric acid, glutaric acid, glutamic acid, glycolic acid, propionic acid, fumaric acid, salicylic acid, pimelic acid, benzoic acid, butyric acid, aspartic acid, sulfonic acid, phthalic acid, vinyl sulfonic acid, methyl sulfonic acid, methyl ethyl sulfonic acid, toluene sulfonic acid, polyvinyl sulfonic acid, and polybenzene sulfonic acid.

[0014] The above titanium nitride film polishing modifier may be included in an amount of 0.005% to 5% by weight relative to the total weight of the metal film polishing slurry composition.

[0015] The film to be polished in the above metal film polishing slurry composition may include titanium, titanium nitride, or both.

[0016] The polishing rate of the titanium nitride film of the above metal film polishing slurry composition may be 1000 Å / min to 2000 Å / min.

[0017] The polishing target film of the above metal film polishing slurry composition comprises titanium nitride and silicon nitride, and the polishing selectivity ratio of the titanium nitride film to the silicon nitride film of the metal film polishing slurry composition may be 400 to 2000.

[0018]

[0019] A metal film polishing method according to one embodiment may include the step of polishing a film to be polished comprising titanium, titanium nitride, or both, using a slurry composition for polishing a metal film. The slurry composition for polishing a metal film may include colloidal silica polishing particles; an oxidizing agent; and a titanium nitride film polishing control agent.

[0020] The metal film polishing slurry composition of the present invention can minimize the occurrence of secondary defects such as voids, dishing, and erosion while securing a polishing rate and polishing selectivity ratio for titanium nitride films.

[0021] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

[0022] Figure 1 is a diagram showing the results of evaluating the titanium nitride film polishing rate of a metal film polishing slurry composition according to one embodiment.

[0023] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, various modifications may be made to the embodiments, and thus the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, and substitutions to the embodiments are included within the scope of the rights.

[0024] The terms used in the embodiments are for illustrative purposes only and should not be interpreted as intended to be limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0025] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments pertain. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0026] In addition, when describing with reference to the attached drawings, identical components are assigned the same reference numeral regardless of drawing symbols, and redundant descriptions thereof are omitted. When describing embodiments, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of the embodiment, such detailed description is omitted.

[0027] In addition, terms such as first, second, A, B, (a), (b), etc. may be used when describing the components of the embodiments. These terms are used only to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by the terms.

[0028] Components included in any one embodiment and components having common functions shall be described using the same names in other embodiments. Unless otherwise stated, the descriptions given in any one embodiment may also apply to other embodiments, and specific descriptions shall be omitted to the extent of overlap.

[0029] Throughout the specification, when a part is described as "including" a certain component, this means that it does not exclude other components but may include additional components.

[0030]

[0031] According to one embodiment of the present invention, a slurry composition for polishing a metal film is provided, comprising colloidal silica abrasive particles; an oxidizing agent; and a titanium nitride film polishing regulator.

[0032] The particle size of the above colloidal silica abrasive particles may be 20 nm to 200 nm, preferably 20 nm to 100 nm, and more preferably 30 nm to 50 nm. If the particle size of the colloidal silica abrasive particles exceeds the upper limit, the desired polishing rate may not be obtained, and there may be problems such as defects or scratches occurring after polishing. If it falls below the lower limit, there may be problems such as insufficient polishing and a decrease in the polishing rate.

[0033] In addition, the colloidal silica abrasive particles may be included in an amount of 0.0001% to 1% by weight relative to the total weight of the slurry composition for polishing a metal film, preferably 0.001% to 0.1% by weight, and more preferably 0.005% to 0.05% by weight or 0.01% to 0.02% by weight. If the content of the colloidal silica abrasive particles falls below the lower limit, a problem may arise in which the polishing speed of the film to be polished decreases, and if it exceeds the upper limit, the number of particles remaining on the surface of the film to be polished increases due to particle adsorption, which may cause surface defects such as defects and scratches.

[0034]

[0035] The above oxidizing agent plays a role in increasing the polishing rate of relatively high-strength titanium and / or titanium nitride by transforming it into a relatively soft film-like metal oxide film through the oxidizing agent. Specifically, it may include at least one selected from the group consisting of hydrogen peroxide, urea hydrogen peroxide, urea, percarbonate, periodic acid, periodate, perchloric acid, perchlorate, perbromic acid, perbromate, perboric acid, perborate, permanganic acid, permanganate, persulfate, bromate, chlorate, hypochlorite, chromate, iodate, iodic acid, ammonium persulfate, benzoyl peroxide, calcium peroxide, barium peroxide, sodium peroxide, and urea peroxide, and preferably may be hydrogen peroxide. Since hydrogen peroxide decomposes relatively easily, it generates a large amount of oxide radicals, allowing it to be used as a powerful oxidizing agent, which has the effect of improving polishing efficiency. Furthermore, because almost no chemical residue remains after the process, it can prevent side effects or the influence of impurities that other types of oxidizing agents may cause.

[0036] At this time, the oxidizing agent may be included in an amount of 0.01% to 5% by weight, preferably 0.05% to 4% by weight, more preferably 0.1% to 3% by weight or 1% to 2% by weight relative to the total weight of the slurry composition for polishing a metal film. If the content of the oxidizing agent falls below the lower limit, the polishing speed of the film to be polished may decrease, and if it exceeds the upper limit, the film surface may be excessively etched, causing secondary problems such as dishing or erosion.

[0037]

[0038] Meanwhile, the titanium nitride film polishing regulator controls the polishing rate of the titanium nitride film to prevent secondary defects such as voids, scratches, and dishing. Specifically, regarding TiN voids generated during the titanium nitride film deposition process, if polishing is performed using a polishing slurry containing an oxidizing agent, a problem may arise where the TiN voids generated during the deposition process grow larger during the polishing process due to the high content of oxidizing agent and particles in the slurry. However, a metal film polishing slurry composition according to one embodiment includes a titanium nitride film polishing regulator to control the polishing speed of the titanium nitride film, thereby minimizing the occurrence of such voids.

[0039] The above titanium nitride film polishing modifier may use an organic acid having a pKa value of -6 to 6, and specifically, may include one or more selected from the group consisting of oxalic acid, malonic acid, citric acid, malic acid, maleic acid, formic acid, lactic acid, acetic acid, picolinic acid, succinic acid, tartaric acid, glutaric acid, glutamic acid, glycolic acid, propionic acid, fumaric acid, salicylic acid, pimelic acid, benzoic acid, butyric acid, aspartic acid, sulfonic acid, phthalic acid, vinyl sulfonic acid, methyl sulfonic acid, methyl ethyl sulfonic acid, toluene sulfonic acid, polyvinyl sulfonic acid, and polybenzene sulfonic acid.

[0040] At this time, the titanium nitride film polishing regulator may be included in an amount of 0.005% to 5% by weight, preferably 0.01% to 1% by weight, more preferably 0.05% to 0.5% by weight or 0.1% to 0.2% by weight relative to the total weight of the metal film polishing slurry composition. If the content of the titanium nitride film polishing regulator exceeds the upper limit, the polishing of the titanium nitride film may be excessively suppressed, which may cause a problem of degrading pattern performance, and if it falls below the lower limit, the effect of improving secondary defects such as dishing, voids, and scratches may be reduced.

[0041]

[0042] Meanwhile, the film to be polished in the slurry composition for polishing a metal film according to one embodiment may include titanium (Ti), titanium nitride (TiN), or both titanium and titanium nitride. Since titanium and titanium nitride films have relatively high strength, and in particular, titanium nitride films have excellent hardness and wear resistance, when the film to be polished in the CMP process includes titanium (Ti) and / or titanium nitride (TiN), a slurry composition for polishing a metal film capable of effectively polishing it must be used. At this time, since it is difficult to efficiently remove the aforementioned film to be polished by mechanical polishing alone, an oxidizing agent can be used to oxidize the surface of titanium (Ti) or titanium nitride (TiN), and the metal oxide layer has lower hardness compared to the existing metal film, so it can be easily removed during the polishing process.

[0043] In addition, voids occur in titanium nitride (TiN) during the deposition process of the pattern film. When a titanium nitride film with voids is polished using a polishing slurry composition containing the aforementioned oxidizing agent, a problem may arise in which the voids gradually enlarge due to the high content of the oxidizing agent and polishing particles. A metal film polishing slurry composition according to one embodiment has the effect of reducing void generation by including a titanium nitride film polishing control agent.

[0044]

[0045] When polishing a titanium nitride film using a slurry composition for polishing a metal film according to one embodiment, the polishing rate for the titanium nitride film may be 1000 Å / min to 2000 Å / min, or 1300 Å / min to 1900 Å / min, or 1400 Å / min to 1800 Å / min. Additionally, when polishing a film to be polished comprising titanium nitride and silicon nitride using the slurry composition for polishing a metal film, the polishing selectivity ratio of the titanium nitride film to the silicon nitride film may be 400 to 2000, or 1000 to 2000, or 1500 to 2000. The slurry composition for polishing a metal film according to one embodiment has the effect of reducing defects in the film to be polished while ensuring a polishing rate of the titanium nitride film at a desired level and exhibiting an excellent polishing selectivity ratio to the silicon nitride film.

[0046]

[0047] The present invention will be explained in more detail below through examples. The following examples are described for the purpose of illustrating the present invention and do not limit the scope of the present invention.

[0048]

[0049] [Example]

[0050] 1. Preparation Example

[0051] Example 1

[0052] A metal film polishing slurry composition was prepared by adding 0.01 wt% of colloidal silica polishing particles having a particle size of 40 nm (relative to the total weight of the metal film polishing slurry composition), 2 wt% of hydrogen peroxide (H2O2) as an oxidizing agent, and 0.1 wt% of oxalic acid as a titanium nitride film polishing regulator, and adjusting the pH of the composition to 2.5.

[0053]

[0054] Example 2

[0055] A slurry composition for polishing a metal film was prepared in the same manner as in Example 1, except that colloidal silica abrasive particles having a particle size of 70 nm were used as abrasive particles.

[0056]

[0057] Example 3

[0058] A slurry composition for polishing a metal film was prepared in the same manner as in Example 1, except that colloidal silica abrasive particles having a particle size of 120 nm were used as abrasive particles.

[0059]

[0060] Example 4

[0061] A slurry composition for polishing a metal film was prepared in the same manner as in Example 1, except that the pH of the composition was adjusted to 10.

[0062]

[0063] Example 5

[0064] A slurry composition for polishing a metal film was prepared in the same manner as in Example 2, except that the pH of the composition was adjusted to 10.

[0065]

[0066] Example 6

[0067] A slurry composition for polishing a metal film was prepared in the same manner as in Example 3, except that the pH of the composition was adjusted to 10.

[0068]

[0069] Example 7

[0070] A slurry composition for polishing a metal film was prepared in the same manner as in Example 1, except that malonic acid was used as a titanium nitride film polishing modifier.

[0071]

[0072] Example 8

[0073] A slurry composition for polishing a metal film was prepared in the same manner as in Example 7, except that colloidal silica abrasive particles having a particle size of 70 nm were used as abrasive particles.

[0074]

[0075] Example 9

[0076] A slurry composition for polishing a metal film was prepared in the same manner as in Example 7, except that colloidal silica abrasive particles having a particle size of 120 nm were used as abrasive particles.

[0077]

[0078] Example 10

[0079] A slurry composition for polishing a metal film was prepared in the same manner as in Example 7, except that the pH of the composition was adjusted to 10.

[0080]

[0081] Example 11

[0082] A slurry composition for polishing a metal film was prepared in the same manner as in Example 8, except that the pH of the composition was adjusted to 10.

[0083]

[0084] Example 12

[0085] A slurry composition for polishing a metal film was prepared in the same manner as in Example 9, except that the pH of the composition was adjusted to 10.

[0086]

[0087] Example 13

[0088] A slurry composition for polishing a metal film was prepared in the same manner as in Example 1, except that citric acid was used as a titanium nitride film polishing modifier.

[0089]

[0090] Example 14

[0091] A slurry composition for polishing a metal film was prepared in the same manner as in Example 13, except that colloidal silica abrasive particles having a particle size of 70 nm were used as abrasive particles.

[0092]

[0093] Example 15

[0094] A slurry composition for polishing a metal film was prepared in the same manner as in Example 13, except that colloidal silica abrasive particles having a particle size of 120 nm were used as abrasive particles.

[0095]

[0096] Example 16

[0097] A slurry composition for polishing a metal film was prepared in the same manner as in Example 13, except that the pH of the composition was adjusted to 10.

[0098]

[0099] Example 17

[0100] A slurry composition for polishing a metal film was prepared in the same manner as in Example 14, except that the pH of the composition was adjusted to 10.

[0101]

[0102] Example 18

[0103] A slurry composition for polishing a metal film was prepared in the same manner as in Example 15, except that the pH of the composition was adjusted to 10.

[0104]

[0105] Comparative Example 1

[0106] A slurry composition for polishing a metal film was prepared in the same manner as in Example 1, except that it did not contain a titanium nitride film polishing modifier.

[0107]

[0108] Comparative Example 2

[0109] A slurry composition for polishing a metal film was prepared in the same manner as in Example 2, except that it did not contain a titanium nitride film polishing modifier.

[0110]

[0111] Comparative Example 3

[0112] A slurry composition for polishing a metal film was prepared in the same manner as in Example 3, except that it did not contain a titanium nitride film polishing modifier.

[0113]

[0114] 2. Experimental Example 1

[0115] Using the compositions of Examples 1 to 18 and Comparative Examples 1 to 3, the polishing rate for titanium nitride films and silicon nitride films was measured under the following conditions, and the polishing selectivity ratio was calculated and shown in Figure 1 and Table 1.

[0116]

[0117] Polishing evaluation conditions

[0118] Polishing Equipment : SP #03

[0119] Grinding pressure: 1.0 psi

[0120] Grinding speed: 93 (platen) / 94 (carrier) rpm

[0121] TiN Polishing Rate (Å / min) SiN Polishing Rate (Å / min) Polishing Selectivity Ratio (TiN / SiN) Example 1 1742 11742 Example 2 17532877 Example 3 17613587 Example 4 175411754 Example 5 17842892 Example 6 17693590 Example 7 164511645 Example 8 16552828 Example 9 16483549 Example 10 165911659 Example 11 16532827 Example 12 16503550 Example 13 155811558 Example 14 15542777 Example 15 15523517 Example 16154811548 Example 1715342767 Example 1815393513 Comparative Example 1291212912 Comparative Example 2287312873 Comparative Example 3291512915

[0122] Referring to Table 1 and Figure 1, it can be seen that the composition of the example containing a titanium nitride film polishing regulator exhibits a lower titanium nitride film polishing rate compared to the composition of the comparative example that does not contain a titanium nitride film polishing regulator. Therefore, it can be seen that when polishing a film to be polished using the metal film polishing slurry composition of the present invention, the polishing speed and polishing selectivity of the titanium nitride film are adjusted to an appropriate level, thereby exhibiting a sufficient polishing rate for the film to be polished while improving secondary defects that may occur due to polishing, such as dishing, erosion, and voids. Furthermore, through a comparison between the compositions of Examples 1 to 3, 7 to 9, and 13 to 15 with the pH adjusted to 2, and Examples 4 to 6, 10 to 12, and 16 to 18 with the pH adjusted to 10, it can be seen that the slurry composition of the present invention exhibits similar performance regardless of pH.

[0123]

[0124] 3. Experimental Example 2: Evaluation of Dynamic Etch Rate

[0125] A wafer was immersed in each of the compositions of Examples 1 to 18 and Comparative Examples 1 to 3 at 60 ℃ and stirred at 100 rpm for 1 minute, then the wafer was dried and the difference in wafer thickness before and after immersion was calculated and shown in Table 2 below.

[0126] DER(Å / min) Example 1 23.6 Example 2 23.4 Example 3 22.4 Example 4 22.1 Example 5 23.5 Example 6 22.8 Example 7 21.3 Example 8 21.1 Example 9 20.4 Example 10 19.4 Example 11 18.6 Example 12 17.6 Example 13 18.5 Example 14 15.3 Example 15 14.1 Example 16 13.4 Example 17 13.5 Example 18 13.4 Comparative Example 17 0.4 Comparative Example 27 3.6 Comparative Example 37 1.1

[0127] Referring to Table 2, it can be seen that the composition of the example containing the titanium nitride film polishing regulator exhibits a lower dynamic etch rate for the titanium nitride film compared to the composition of the comparative example that does not contain the titanium nitride film polishing regulator. Therefore, when polishing a film to be polished using the TiN polishing slurry composition of the present invention, it can be seen that the polishing speed and polishing selectivity of the titanium nitride film are controlled to an appropriate level, thereby exhibiting a sufficient polishing rate for the film to be polished while improving secondary defects that may occur due to polishing, such as dishing, erosion, and voids.

[0128] Although the embodiments have been described above with reference to limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, suitable results can be achieved even if the described techniques are performed in a different order than the described method, and / or the described components are combined or assembled in a form different from the described method, or are replaced or substituted by other components or equivalents.

[0129] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below.

Claims

1. Colloidal silica abrasive particles; Oxidizing agent; and containing a titanium nitride film polishing modifier, Slurry composition for polishing metal films.

2. In Paragraph 1, The particle size of the above colloidal silica abrasive particles is 20 nm to 200 nm, Slurry composition for polishing metal films.

3. In Paragraph 1, The above colloidal silica abrasive particles are included in an amount of 0.0001% to 1% by weight relative to the total weight of the metal film polishing slurry composition, Slurry composition for polishing metal films.

4. In Paragraph 1, The above oxidizing agent comprises at least one selected from the group consisting of hydrogen peroxide, hydrogen peroxide, urea, percarbonate, periodic acid, periodate, perchloric acid, perchlorate, perbromic acid, perbrodate, perboric acid, perborate, permanganic acid, permanganate, persulfate, bromate, chlorate, hypochlorite, chromate, iodate, iodic acid, ammonium persulfate, benzoyl peroxide, calcium peroxide, barium peroxide, sodium peroxide, and urea peroxide. Slurry composition for polishing metal films.

5. In Paragraph 1, The above oxidizing agent is included in an amount of 0.05% to 4% by weight relative to the total weight of the metal film polishing slurry composition, Slurry composition for polishing metal films.

6. In Paragraph 1, The above titanium nitride film polishing regulator is pK a organic acids with a value of -6 to 6, Slurry composition for polishing metal films.

7. In Paragraph 1, The titanium nitride film polishing modifier comprises one or more selected from the group consisting of oxalic acid, malonic acid, citric acid, malic acid, maleic acid, formic acid, lactic acid, acetic acid, picolinic acid, succinic acid, tartaric acid, glutaric acid, glutamic acid, glycolic acid, propionic acid, fumaric acid, salicylic acid, pimelic acid, benzoic acid, butyric acid, aspartic acid, sulfonic acid, phthalic acid, vinyl sulfonic acid, methyl sulfonic acid, methyl ethyl sulfonic acid, toluene sulfonic acid, polyvinyl sulfonic acid, and polybenzene sulfonic acid. Slurry composition for polishing metal films.

8. In Paragraph 1, The above titanium nitride film polishing modifier is included in an amount of 0.005% to 5% by weight relative to the total weight of the metal film polishing slurry composition, Slurry composition for polishing metal films.

9. In Paragraph 1, The film to be polished of the above metal film polishing slurry composition is titanium, titanium nitride, or a combination of both. Slurry composition for polishing metal films.

10. In Paragraph 1, The polishing rate of the above metal film polishing slurry composition for a titanium nitride film is 1000 Å / min to 2000 Å / min, Slurry composition for polishing metal films.

11. In Paragraph 1, The film to be polished of the above metal film polishing slurry composition comprises titanium nitride and silicon nitride, and A polishing selectivity ratio of titanium nitride film to silicon nitride film of 400 to 2000, Slurry composition for polishing metal films.

12. A step of polishing a film to be polished comprising titanium, titanium nitride, or both, using the metal film polishing slurry composition of claim 1, A metal film polishing method comprising

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