Chemical mechanical polishing composition and application thereof in copper chemical mechanical polishing

Abstract

The invention belongs to the technical field of chemical mechanical polishing, and particularly relates to a chemical mechanical polishing composition and application thereof in copper chemical mechanical polishing. The chemical mechanical polishing composition provided by the invention can effectively perform chemical mechanical polishing of copper, simplify the polishing process and improve the productivity. The chemical mechanical polishing composition comprises grinding particles, a first corrosion inhibitor, a second corrosion inhibitor, a complexing agent, a surfactant, a pH regulator, an oxidizing agent and a solvent, the structural formula of the first corrosion inhibitor is shown as a formula I, and the structural formula of the second corrosion inhibitor is shown as a formula II. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of chemical mechanical polishing, and in particular relates to a chemical mechanical polishing composition and application thereof in chemical mechanical polishing of copper. Background Art

[0002] Very large-scale integrated circuit wiring is transforming from traditional aluminum wiring process to copper wiring process. At present, chemical mechanical polishing is the most effective process method for copper wiring flattening. Generally, the chemical mechanical polishing process of copper is divided into three steps: the first step is to use a higher down pressure (1.5-2.0psi) to remove a large amount of copper on the surface of the substrate at a fast and efficient removal rate and leave a certain thickness of copper; the second step is to use a lower down pressure (0.5-1.0psi) to remove a small amount of remaining metal copper at a lower removal rate and stop on the barrier layer; the third step is to use a barrier layer polishing liquid to remove the barrier layer, part of the dielectric layer and a small amount of metal copper to achieve flattening. At present, all three steps of polishing require sufficient time, which makes the copper polishing process a bottleneck of production capacity.

[0003] In order to increase the polishing rate, people are trying to merge the first two steps of copper polishing into one step. When these two steps are merged into one step (high pressure first and then low pressure) for polishing, the existing chemical mechanical polishing composition cannot meet the polishing requirements. The chemical mechanical polishing composition involving copper generally includes abrasive particles, corrosion inhibitors, complexing agents, wetting agents, pH regulators, oxidants, etc. In order to achieve a higher removal rate, a weaker corrosion inhibitor is usually selected, and the polishing rate is regulated by changing the polishing pressure. When the two steps are combined into one step for polishing, after the high pressure is converted into low pressure, the corrosion inhibitor cannot be fully adsorbed on the copper surface, and after a certain period of high pressure polishing, the temperature of the polishing pad is high, thereby accelerating the corrosion rate of the copper surface, making the low pressure polishing rate higher, affecting the flattening effect.

[0004] US20030008599A1 discloses that the polishing rate of copper can be regulated by introducing an oxidant and a reductant at different stages of the polishing process; US20100130101A1 discloses that different polishing liquid components are introduced into the polishing pad through two pipelines, the polishing liquid is mixed online for polishing, and the polishing rate is regulated by adjusting the flow of different components; CN103903979A also reports that the polishing rate is regulated by supplying a polishing liquid and a polishing rate inhibitor through two pipelines respectively. The above methods all have two problems. The first is that the chemical components are mixed online, and there is a problem of uneven mixing, which brings great risks to the polishing flatness and wafer polishing consistency; the second is that the materials of different components are mixed after polishing, which is easy to cause the aggregation of abrasive nanoparticles, which will shorten the service life of the polishing pad and easily clog the drain pipe of the polishing machine.

[0005] Therefore, how to develop a new chemical mechanical polishing (CMP) composition that can effectively perform chemical mechanical polishing of copper, simplify the polishing process, and improve production capacity are issues that need to be addressed. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention obtains a new chemical mechanical polishing composition by specifically selecting and optimizing the corrosion inhibitor and the solvent. The composition can meet the use requirements of combining the first two steps into one step of polishing, thereby achieving the effect of simplifying the copper polishing process and improving production capacity.

[0007] Specifically, the present invention is realized through the following technical solutions:

[0008] In a first aspect, the present invention provides a chemical mechanical polishing composition, comprising abrasive particles, a first corrosion inhibitor, a second corrosion inhibitor, a complexing agent, a surfactant, a pH adjuster, an oxidant and a solvent, wherein the first corrosion inhibitor has a structure shown in Formula I, the second corrosion inhibitor has a structure shown in Formula II,

[0009]

[0010] In formula (I), R1 is selected from C1-C 20 Aliphatic alkyl and C1-C 20 aliphatic alkoxy, n is selected from an integer between 1 and 4;

[0011] In formula (II), R2 is methyl or methoxy, and n is selected from an integer between 0 and 4;

[0012] The first corrosion inhibitor and the second corrosion inhibitor are different.

[0013] In a preferred embodiment, based on the total weight of the chemical mechanical polishing composition, the total content of the first corrosion inhibitor and the second corrosion inhibitor is 0.01 wt%-3 wt%. In a more preferred embodiment, based on the total weight of the chemical mechanical polishing composition, the total content of the first corrosion inhibitor and the second corrosion inhibitor is 0.01 wt%-2 wt%.

[0014] In a preferred embodiment, the first corrosion inhibitor is selected from the following structures:

[0015]

[0016]

[0017] In a preferred embodiment, the second corrosion inhibitor is selected from the following structures:

[0018]

[0019] In a preferred embodiment, the weight ratio of the first corrosion inhibitor to the second corrosion inhibitor is 1:(0.1-10). In a specific embodiment, the weight ratio of the first corrosion inhibitor to the second corrosion inhibitor is 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or in the range of any two of the above values. In a most preferred embodiment, the weight ratio of the first corrosion inhibitor to the second corrosion inhibitor is 1:1.

[0020] In a preferred embodiment, the solvent comprises a first component and a second component, wherein the first component is water and the second component is an organic solvent. In a further preferred embodiment, the second component is selected from aliphatic alcohols. In a more preferred embodiment, the second component is selected from methanol, ethanol, propanol, butanol, pentanol, hexanol, ethylene glycol and glycerol. In a most preferred embodiment, the second component is glycerol.

[0021] In a preferred embodiment, the weight ratio of the first component to the second component of the solvent is 1:0.4-2.3. In a specific embodiment, the weight ratio of the first component to the second component of the solvent is 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0, 1:2.1, 1:2.2, 1:2.3 or in the range of any two of the above values.

[0022] In a preferred embodiment, the abrasive particles are silicon dioxide nanoparticles or aluminum oxide nanoparticles. In a more preferred embodiment, the abrasive particles are silicon dioxide nanoparticles with a particle size of 30-160 nm.

[0023] In a preferred embodiment, the complexing agent is selected from one or more of arginine, lysine, glycine, citric acid, phosphoric acid, amino tris(methylene phosphonic acid), hydroxy ethylidene diphosphonic acid, ethylenediamine tetra(methylene phosphonic acid) and hydroxy ethylidene diphosphonic acid. In a more preferred embodiment, the complexing agent is glycine.

[0024] In a preferred embodiment, the surfactant is a polymer anionic surfactant selected from one or more of a carboxylate-sulfonate copolymer, a carboxylate-sulfonate-nonionic copolymer and a carboxylate-sulfonate-acrylate copolymer having a hydrophilic-hydrophobic balance value of 15-30, wherein the salt is a potassium salt and / or a sodium salt. In a more preferred embodiment, the surfactant is a carboxylic acid-sulfonate copolymer KR-5000.

[0025] In a preferred embodiment, the pH adjuster is selected from one or more of H3PO4, HNO3, potassium hydroxide and ammonium hydroxide.

[0026] In a preferred embodiment, the oxidizing agent is hydrogen peroxide.

[0027] In a preferred embodiment, based on the total weight of the chemical mechanical polishing composition, the content of the abrasive particles is 0.5 wt % to 3 wt %.

[0028] In a preferred embodiment, the content of the complexing agent is 1 wt % to 20 wt % based on the total weight of the chemical mechanical polishing composition.

[0029] In a preferred embodiment, based on the total weight of the chemical mechanical polishing composition, the content of the surfactant is 0.005 wt % to 3 wt %.

[0030] In a preferred embodiment, the content of the oxidizing agent is 0.1 wt % to 1 wt % based on the total weight of the chemical mechanical polishing composition.

[0031] In a preferred embodiment, the second component is present in an amount of at least 30 wt % based on the total weight of the chemical mechanical polishing composition. In a specific embodiment, based on the total weight of the chemical mechanical polishing composition, the content of the second component is 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt%, 38wt%, 39wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49wt%, 50wt%, 51wt%, 52wt%, 53wt%, 54wt%, 55wt%, 56wt%, 57wt%, 58wt%, 59wt%, 60wt%, 61wt%, 62wt%, 63wt%, 64wt%, 65wt%, 66wt%, 67wt%, 68wt%, 69wt%, 70wt% or in the range of any two of the above values.

[0032] In a preferred embodiment, the pH range of the chemical mechanical polishing composition is 5-8. In a more preferred embodiment, the pH range of the chemical mechanical polishing composition is 6-7.

[0033] In a preferred embodiment, based on the total weight of the chemical mechanical polishing composition, the content of the abrasive particles is 0.5wt%-3wt%, the total content of the first corrosion inhibitor and the second corrosion inhibitor is 0.01%-3%, the content of the complexing agent is 1wt%-20wt%, the content of the surfactant is 0.005wt%-3wt%, the content of the oxidant is 0.1wt%-1wt%, and the balance is solvent.

[0034] In a second aspect, the present invention provides the use of the chemical mechanical polishing composition described in the first aspect in chemical mechanical polishing of copper. In a preferred embodiment, the polishing method comprises the following steps: (1) the chemical mechanical polishing composition is sequentially applied under high pressure (1.5-2.0 psi) and low pressure (0.5-1.0 psi) to remove copper on the surface of the substrate and stop on the barrier layer; (2) the barrier layer, part of the dielectric layer and a small amount of metallic copper are removed using a barrier layer polishing liquid.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The chemical mechanical polishing composition provided by the present invention adopts two corrosion inhibitors and adds a solvent, so that when polishing under high pressure, the first corrosion inhibitor is difficult to adsorb on the surface of copper, thereby obtaining a faster polishing rate. When polishing under low pressure, the first corrosion inhibitor and the second corrosion inhibitor are simultaneously adsorbed on the surface of copper, thereby reducing the polishing rate. The chemical mechanical polishing composition of the present invention can meet the use requirement of combining the first two steps of copper metal polishing into one step of polishing (first high pressure and then low pressure), thereby achieving the effect of simplifying the copper polishing process and improving production capacity. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below. The embodiments are given to better illustrate the contents of the present invention and are only used to explain the present invention, but should not be understood as limiting the present invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The term "and / or" as may be used herein includes any and all combinations of one or more of the related listed items. The terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

[0039] As used herein, wt% means weight percent.

[0040] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0041] Example

[0042] The components of the chemical mechanical polishing composition are shown in Table 1 below, wherein the respective parts are parts by weight, the abrasive particles are silicon dioxide nanoparticles, the surfactant is a carboxylic acid-sulfonate copolymer kr-5000 purchased from Shandong Kairui Chemical, the first component of the solvent is water, and the oxidant uses hydrogen peroxide, and the hydrogen peroxide (the amount of pure hydrogen peroxide) accounts for 0.4 wt% of the total weight of the copper chemical mechanical polishing composition.

[0043] The preparation of the polishing composition includes: stirring and mixing various components evenly, adjusting the pH value to 6 with HNO3 or potassium hydroxide; adding an oxidant before use and mixing evenly.

[0044] The specific polishing conditions are as follows: the polishing machine is 12” Reflexion LK, the polishing pad is IC1010; the high polishing pressure is 2.0psi, the low polishing pressure is 1.0psi; the polishing head and polishing disc speed is 93 / 87rpm, the polishing liquid flow rate is 300mL / min, and the polishing time is 2min. One-step polishing of metal copper is performed (first high pressure polishing for 1min, then low pressure polishing for 1min), and the polishing rate of the copper wafer under different pressure conditions is calculated based on the real-time thickness change of the copper wafer during the polishing process and combined with the metal film thickness meter.

[0045] Table 1

[0046]

[0047]

[0048] Generally speaking, under high pressure, the copper polishing rate needs to be greater than 6000A / min, and under low pressure, the copper polishing rate needs to be between 1500-2200A / min.

[0049] From the experimental results of Comparative Example 1 using only the first corrosion inhibitor, the removal rate of copper under high pressure is only 3421A / min, which is far lower than the minimum requirement of 6000A / min for the polishing rate of copper under high pressure, and the removal rate of copper under low pressure is only 1028A / min, which is also far lower than the required range of 1500-2200A / min for the polishing rate of copper under low pressure. Obviously, both do not meet the requirements. From the experimental results of Comparative Example 2 using only the second corrosion inhibitor, although it meets the requirements of the removal rate of copper under high pressure, the removal rate of copper under low pressure reaches 2896A / min, which obviously exceeds the required range of 1500-2200A / min for the polishing rate of copper under low pressure. From the experimental results of Example 5, it can be seen that under the same other parameters, the chemical mechanical composition containing both the first corrosion inhibitor and the second corrosion inhibitor has a copper polishing rate of 6789A / min under high pressure and a copper polishing rate of 1822A / min under low pressure, both of which meet the requirements.

[0050] By comparing Examples 5 to 7 of the present invention, it can be seen that, compared with n-butanol and ethylene glycol, when glycerol is used as the second component of the solvent, the polishing rate under high pressure is the highest, reaching more than 7000 A / min. In addition, glycerol has a high boiling point and is safe to use, and can be used as a preferred second component of the solvent.

[0051] By comparing Examples 7 to 9 of the present invention, it can be seen that as the weight proportion of the second component glycerol as the solvent becomes lower and lower, the polishing rate under high pressure shows a downward trend. When the weight proportion of glycerol drops below 30, the polishing rate under high pressure decreases significantly, even close to 5000 A / min. Therefore, when glycerol is selected as the second component of the solvent, its weight proportion is 30 or more.

[0052] By comparing Example 10 of the present invention with Example 7, it can be seen that when citric acid is used as the complexing agent, the polishing rate under high pressure and the polishing rate under low pressure are both reduced. The polishing rate under high pressure using citric acid as the complexing agent is close to 6000A / min, and the polishing rate under low pressure is close to 1500A / min, which just reaches the minimum requirement for the polishing rate of copper; while the polishing rate under high pressure using glycine as the complexing agent is more than 7000A / min, and the polishing rate under low pressure is more than 1900A / min, and the polishing rate under high pressure and the polishing rate under low pressure are both high. Therefore, glycine can be used as a preferred complexing agent.

[0053] Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A chemical mechanical polishing composition, It is characterized in that The chemical mechanical polishing composition comprises abrasive particles, a first corrosion inhibitor, a second corrosion inhibitor, a complexing agent, a surfactant, a pH adjuster, an oxidant and a solvent, wherein the first corrosion inhibitor has a structure shown in Formula I, and the second corrosion inhibitor has a structure shown in Formula II. In formula (I), R 1 Selected from C 1 -C 20 The aliphatic alkyl and C 1 -C 20 aliphatic alkoxy, n is selected from an integer between 1 and 4; In formula (II), R 2 is a methyl group or a methoxy group, n is selected from an integer between 0 and 4, and the first corrosion inhibitor and the second corrosion inhibitor are different.

2. The chemical mechanical polishing composition according to claim 1, It is characterized in that Based on the total weight of the chemical mechanical polishing composition, the total content of the first corrosion inhibitor and the second corrosion inhibitor is 0.01 wt % to 3 wt %.

3. The chemical mechanical polishing composition according to claim 1, It is characterized in that The first corrosion inhibitor is selected from the following structures: and / or The second corrosion inhibitor is selected from the following structures:

4. The chemical mechanical polishing composition according to any one of claims 1 to 3, It is characterized in that The weight ratio of the first corrosion inhibitor to the second corrosion inhibitor is 1:(0.1-10); and / or the solvent comprises a first component and a second component, wherein the first component is water and the second component is an organic solvent; and / or The abrasive particles are silicon dioxide nanoparticles or aluminum oxide nanoparticles; and / or The complexing agent is selected from one or more of arginine, lysine, glycine, citric acid, phosphoric acid, aminotri(methylenephosphonic acid), hydroxyethylidene diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid) and hydroxyethylidene diphosphonic acid; and / or The surfactant is a polymer anionic surfactant selected from one or more of a carboxylate-sulfonate copolymer, a carboxylate-sulfonate-nonionic copolymer and a carboxylate-sulfonate-acrylate copolymer having a hydrophilic-hydrophobic balance value of 15-30; and / or The pH adjusting agent is selected from H 3 PO 4 , HNO 3 , potassium hydroxide and ammonium hydroxide; and / or The oxidant is hydrogen peroxide.

5. The chemical mechanical polishing composition according to claim 4, It is characterized in that The second component is selected from aliphatic alcohols; and / or The abrasive particles are silicon dioxide nanoparticles with a particle size of 30-160 nm; and / or The complexing agent is glycine; and / or The surfactant is carboxylic acid-sulfonate copolymer KR-5000.

6. The chemical mechanical polishing composition according to claim 5, It is characterized in that The second component is selected from the group consisting of methanol, ethanol, propanol, butanol, pentanol, hexanol, ethylene glycol and glycerol.

7. The chemical mechanical polishing composition according to claim 6, It is characterized in that The second component is glycerol; and / or The second component is present in an amount of at least 30 wt % based on the total weight of the chemical mechanical polishing composition.

8. The chemical mechanical polishing composition according to any one of claims 1 to 3, It is characterized in that Based on the total weight of the chemical mechanical polishing composition, the total content of the first corrosion inhibitor and the second corrosion inhibitor is 0.01%-2%; and / or The content of the abrasive particles is 0.5%-3%; and / or The content of the complexing agent is 1%-20%; and / or The content of the surfactant is 0.005%-3%; and / or The content of the oxidant is 0.1%-1%; and / or The pH range of the chemical mechanical polishing composition is 5-8.

9. The chemical mechanical polishing composition according to claim 8, It is characterized in that The pH range of the chemical mechanical polishing composition is 6-7.

10. Use of the chemical mechanical polishing composition according to any one of claims 1 to 9 in chemical mechanical polishing of copper.

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