CN100336881C - Chemical Mechanical Polishing Slurry Compositions and Methods of Using the Same - Google Patents

Abstract

The invention provides a chemical mechanical grinding slurry composition used in a semiconductor preparation process, which comprises 70-99.5 wt% of an aqueous medium; 0.1-25 wt% abrasive particles; 0.01-1 wt% of a corrosion inhibitor; and 0.01 to 1% of a chemical selected from the group consisting of a dialdehydeate, a 2-hydroxycarboxylic acid compound, and mixtures thereof. The chemical mechanical polishing slurry composition of the present invention may further comprise an oxidizing agent, if necessary. The invention also relates to a method for polishing the surface of a semiconductor wafer by using the composition.

Description

Chemical Mechanical Polishing Slurry Compositions and Methods of Using the Same

technical field

The invention relates to a chemical mechanical polishing slurry composition. The polishing composition of the present invention can be effectively applied to polishing the surface of a semiconductor wafer.

Background technique

Chemical Mechanical Polishing (CMP for short) is a planarization technology developed to solve the difficulty of focusing in the lithography preparation process due to the difference in coating height during the manufacture of integrated circuits (IC). CMP technology was first applied in a small amount in the manufacture of 0.5 micron components. As the size shrinks, the number of layers applied by CMP is also increasing. By the 0.25 micron generation, chemical mechanical polishing has become the mainstream and necessary planarization technology. Generally speaking, the grinding method for manufacturing metal circuits is to place a semiconductor wafer on a rotating grinding table equipped with a grinding head, and apply a grinding slurry containing grinding particles and an oxidizing agent on the surface of the wafer to improve grinding performance.

US Patent No. 5,225,034 discloses a chemical mechanical polishing slurry comprising AgNO ₃ , solid abrasive material, and an oxidizing agent selected from H ₂ O ₂ , HOCl, KOCl, KMgO ₄ or CH ₃ COOOH. The polishing slurry is used to polish the copper layer on the semiconductor wafer to make the copper wire on the wafer.

U.S. Patent No. 5,209,816 discloses a method for polishing an Al or Ti-containing metal layer using a chemical mechanical polishing slurry. The polishing slurry contains about 0.1-20% by volume of H ₃ PO ₄ and About 1-30% by volume _{of H2O2} .

US Patent No. 4,959,113 relates to a method of polishing metal surfaces using an aqueous abrasive composition. The aqueous abrasive composition comprises water, abrasives (such as CeO ₂ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , SiO ₂ , SiC, SnO ₂ and TiC), and a salt comprising the periodic table of elements A metal cation of Group IIA, IIIA, IVA or IVB and an anion of chloride, bromide, iodide, nitrate, sulfate, phosphate or perchlorate. This US patent also teaches the use of hydrochloric acid, nitric acid, phosphoric acid or sulfuric acid to adjust its aqueous abrasive composition to pH=1-6.

U.S. Patent No. 5,391,258 discloses an abrasive composition for polishing a compound containing silicon, silica or silicate, which, in addition to abrasive particles, also includes hydrogen peroxide and potassium hydrogen phthalate (potassium hydrogen phthalate) .

U.S. Patent No. 5,114,437 relates to a polishing composition for polishing aluminum substrates, which comprises an alumina polishing agent with an average particle size of 0.2 to 5 μm and a polishing agent selected from the group consisting of chromium(III) nitrate, lanthanum nitrate, nitric acid Polishing accelerator for cerium(III) ammonium or neodymium nitrate.

U.S. Patent No. 5,084,071 relates to a method of polishing electronic component substrates using a chemical mechanical polishing slurry containing less than 1% by weight of alumina, abrasive particles (e.g., SiO ₂ , CeO ₂ , SiC, Si ₃ N ₄ or Fe ₂ O ₃ ), a transition metal chelate salt (for example, ferric ammonium EDTA) as a grinding efficiency promoter, and a solvent for the salt.

US Patent No. 5,336,542 discloses a polishing composition comprising alumina abrasive grains and a chelating agent selected from polyaminocarboxylic acids (such as EDTA) or their sodium or potassium salts. The polishing composition may further contain boehmite or aluminum salts.

U.S. Patent No. 5,340,370 discloses a slurry for chemical mechanical polishing of, for example, tungsten or tungsten nitride thin films, which comprises potassium ferricyanide oxidant, abrasive and water for thin films, wherein the slurry has a ratio of 2 to 4 pH.

U.S. Patent No. 5,516,346 discloses a slurry for chemical mechanical polishing of a titanium film comprising potassium fluoride and an abrasive (such as silicon oxide) at a concentration sufficient to complex with the titanium film, wherein the slurry has an pH.

WO 96/16436 discloses a chemical mechanical polishing slurry comprising abrasive particles having a median diameter of less than 0.400 microns, an iron salt oxidizing agent, and an aqueous surfactant suspension of propylene glycol and methylparaben.

The salts commonly used to increase the grinding rate contain iron ions (such as Fe(NO ₃ ) ₃ or K ₃ Fe(CN) ₆ ) or potassium ions (such as KIO ₃ ), however, these metal ions will contaminate the wafer and CMP equipment , increase the workload of post-cleaning and reduce the service life of CMP preparation equipment. In addition, potassium ions are quite mobile and easily penetrate the dielectric layer, reducing the reliability of the IC.

In the IC fabrication process, Ta or TaN films are often used to improve the adhesion of copper to the silicon oxide insulating layer. In addition, a Ta or TaN thin film is also used as the metal of the barrier film. Theoretically, the removal rate of Ta or TaN should be similar to that of Cu, but Ta metal is a metal with high chemical resistance. Because it is not easily oxidized, the grinding of Ta metal has always been a technical problem in the process of copper preparation. The hardest to overcome. At the same time, since the barrier film is difficult to remove, it often leads to the problem of copper wire depression.

In addition, during the copper preparation process, the copper film will undergo annealing treatment, so that a layer of dense copper oxide is likely to be formed on the copper film. Moreover, due to the uniformity problem in the CMP preparation process, when part of the copper on the wafer has been ground off and depressions begin to occur, there will often be undesired copper remaining on the wafer. Therefore, how to quickly remove copper residues to reduce dishing of copper wires and accelerate productivity is a major issue that needs to be overcome in the CMP preparation process.

To sum up, in the semiconductor manufacturing process, there is still an urgent search for a chemical mechanical polishing composition that is more economical, more efficient and can reduce the above-mentioned disadvantages.

Contents of the invention

The invention provides a chemical mechanical polishing slurry composition used in the semiconductor preparation process, which comprises 70-99.5% by weight of an aqueous medium; 0.1-25% by weight of abrasive particles; 0.01-1% by weight of a corrosion inhibitor and 0.01% by weight - 1% by weight of a chemical selected from the group consisting of glycolates, 2-hydroxycarboxylates and mixtures thereof. The chemical mechanical polishing slurry composition of the present invention may further comprise an oxidizing agent. The invention also relates to a method of using the composition for grinding the surface of a semiconductor wafer.

The chemical mechanical polishing slurry composition of the present invention comprises 70-99.5% by weight, preferably 80-99.5% by weight of an aqueous medium; 0.1-25% by weight, preferably 0.5-10% by weight, and more preferably 0.5-5% by weight % of abrasive particles; 0.01-1.0% by weight, more preferably 0.01-0.5% by weight, and most preferably 0.05-0.2% by weight of a corrosion inhibitor; and 0.01-1.0% by weight of a glycolate and 2-hydroxy Carboxylates and their mixtures of chemicals. The chemical mechanical polishing composition of the present invention may further comprise 0.1-5% by weight of an oxidizing agent.

According to the embodiments of the present invention, adding glycolate or 2-hydroxycarboxylate to the polishing slurry can prevent copper pitting.

According to the present invention, the abrasive particles used in the abrasive slurry composition can be commercially available, such as SiO ₂ , Al ₂ O ₃ , ZrO 2 , CeO _{2 ,} SiC, Fe ₂ O ₃ , TiO ₂ , Si ₃ N ₄ or its mixture. These abrasive particles have the advantages of high purity, high specific surface area, and narrow particle size distribution, so they are suitable for use in abrasive compositions as abrasive particles.

The selection of the aqueous medium of the abrasive slurry composition of the present invention is obvious to those skilled in the art. For example, in the preparation process, water, preferably deionized water, can be used to make the abrasive composition slurry. .

According to the present invention, the corrosion inhibitor used in the grinding slurry composition is a triazolide, which can be selected from benzotriazole, cyanuric acid (1,3,5-triazine-2,4,6-triol ( 1,3,5-triazine-2,4,6-triol)), 1,2,3-triazole, 3-amino-1,2,4-triazole, 3-nitro-1,2, 4-triazole, purpald( ^R ), benzotriazole-5-carboxylic acid, 3-amino-1,2,4-triazole-5-carboxylic acid, 1-hydroxybenzotriazole, and nitrobenzotriazoles; preferably benzotriazoles are used.

According to the present invention, the glycol compound used in the abrasive slurry composition is a compound of the following structural formula:

Wherein, R ¹ and R ² are respectively selected from H or C ₁ -C ₆ alkyl. Diol compounds suitable for use in the present invention can be, for example, ethylene glycol, α-propylene glycol, 1,2-butanediol or 2,3-butanediol, preferably ethylene glycol or α-propylene glycol, and most preferably ethylene glycol. According to a preferred embodiment of the present invention, the composition of the present invention comprises 0.01-1.0% by weight, preferably 0.01-0.5% by weight, and more preferably 0.1-0.4% by weight of ethylene glycol.

According to the present invention, the 2-hydroxycarboxylate used in the abrasive slurry composition is a compound of the following structural formula:

Wherein, R is H or C ₁ -C ₆ alkyl. The 2-hydroxycarboxylates suitable for use in the present invention can be, for example, 2-hydroxyacetic acid, 2-hydroxypropionic acid, or 2-hydroxybutyric acid, preferably 2-hydroxyacetic acid or 2-hydroxypropionic acid, and most preferably 2-hydroxyacetic acid. According to a preferred embodiment of the present invention, the composition of the present invention may comprise 0.01-1.0% by weight, preferably 0.01-0.5% by weight, and more preferably 0.1-0.4% by weight of 2-hydroxyacetic acid.

According to the present invention, the oxidizing agent used in the polishing slurry composition is a component known in the field of chemical mechanical polishing, which can be selected from H ₂ O ₂ , Fe(NO ₃ ) ₃ , KIO ₃ , CH ₃ COOOH and KMnO ₄ Form a group; preferably use H ₂ O ₂ .

According to the present invention, when the deionized water is 80-99.5% by weight, the solid content of the slurry is 0.5-15% by weight, preferably 0.5-10% by weight, and more preferably 0.5-5% by weight. The components as described above are then introduced into the resulting high purity slurry, and acid or base is added to control the pH of the slurry within the desired range.

The present invention also relates to a method for polishing the surface of a semiconductor wafer, which comprises applying the chemical mechanical polishing slurry composition according to the present invention on the surface of the wafer.

The following examples will further illustrate the present invention, but are not intended to limit the scope of the present invention. Any modifications and changes that can be easily achieved by those skilled in the art are included in the scope of the present invention.

Example

grinding test

A. Instrument: AMAT/Mirra

B. Conditions: Membrane Pressure: 2psi

Inner Tube: Vent

  Maintaining Ring Pressure (Retaining Ring): 2.6psi

Grinding platform speed (Platen Speed): 93rpm

Carrier Speed: 87rpm

 Temperature: 25°C

  Abrasive Pad Seat Type: IC1000, k-xy.

  Slurry flow rate: 150ml/min

C. Chip: patterned wafer, purchased from Semitech, model: 0.25 μm line width 854CMP017 wafer.

D. Slurry: Take the slurry obtained in the example and 30% H ₂ O ₂ at a volume ratio of 9:1 and uniformly stir it for testing.

Grinding test procedure:

In the present invention, the Mirra grinding machine of Applied Materials is used for grinding, and the signal generated by the End Point System is used as the determination of the end point (EP2) signal during the grinding process. When grinding, grind to EP2 with the slurry in the examples respectively, and then perform 20% over-polishing. After grinding, the wafer was cleaned with Evergreen Model 10X cleaning machine from Solid State Equipment Corporation, and the wafer was blown dry with nitrogen (N ₂ ) after cleaning. Then use the KLA-Tencor P-11 SurfaceProfiler contact surface profiler to measure the degree of copper depression (Disshing). During the measurement, the copper wire with a line width of 100 microns (μm) is used as the measurement point to measure its contact with the barrier layer (Barrier Layer) relative depression.

Example 1

Prepare the slurry with colloidal silica as abrasive particles. The composition of the slurry is as follows, and the grinding test results are shown in Table 1.

Silica gel content: 2.0% by weight; benzotriazole (BTA): 0.1% by weight;

The rest are ammonia water or nitric acid and deionized water to adjust the pH value.

Example 2

The slurry was prepared in the same manner and composition as described in Example 1, but an additional 0.2% by weight of formic acid was added. The grinding test results are shown in Table 1.

Example 3

The slurry was prepared in the same manner and composition as described in Example 1, but 0.2% by weight of adipic acid was additionally added. The grinding test results are shown in Table 1.

Example 4

The slurry was prepared in the same manner and composition as described in Example 1, but additionally added 0.2% by weight of aminoacetic acid, and the grinding test results are shown in Table 1.

Example 5

The slurry was prepared in the same manner and composition as described in Example 2, but 0.2% by weight of ethylene glycol was additionally added. The grinding test results are shown in Table 1.

Example 6

The slurry was prepared in the same manner and composition as described in Example 3, but 0.2% by weight of ethylene glycol was additionally added. The grinding test results are shown in Table 1.

Example 7

The slurry was prepared in the same manner and composition as described in Example 4, but 0.2% by weight of ethylene glycol was additionally added. The grinding test results are shown in Table 1.

Example 8

Same as Example 7, except that the pH value is changed between 5-6, the grinding test results are shown in Table 1.

Example 9

The slurry was prepared in the same manner and composition as described in Example 3, but 0.4% by weight of ethylene glycol was additionally added. The grinding test results are shown in Table 1.

Example 10

It is the same as Example 6, except that alumina is used as the abrasive particle, and the grinding test results are shown in Table 1.

Example 11

It is the same as Example 3, except that alumina is used as the abrasive particle, and the grinding test results are shown in Table 1.

Example 12

The slurry was prepared in the same manner and composition as described in Example 3, but 0.2% by weight of 2-hydroxyacetic acid was additionally added. The grinding test results are shown in Table 1.

Example 13

It is the same as Example 12, except that alumina is used as the abrasive particle, and the grinding test results are shown in Table 1.

Table 1 example Abrasive particle type Solid content (%) Added chemicals and their content (weight %) pH value Notch (A/100μm Cu line width) 1 silica gel 2 Benzotriazole (0.1%) 3-4 1213 2 silica gel 2 Benzotriazole (0.1%) formic acid (0.2%) 3-4 1617 3 silica gel 2 Benzotriazole (0.1%) Adipic acid (0.2%) 3-4 1530 4 silica gel 2 Benzotriazole (0.1%) Glycine (0.2%) 3-4 1593 5 silica gel 2 Benzotriazole (0.1%) formic acid (0.2%) ethylene glycol (0.2%) 3-4 659 6 silica gel 2 Benzotriazole (0.1%) Adipic acid (0.2%) Ethylene glycol (0.2%) 3-4 544 7 silica gel 2 Benzotriazole (0.1%) Glycine (0.2%) Ethylene Glycol (0.2%) 3-4 631 8 silica gel 2 Benzotriazole (0.1%) Adipic acid (0.2%) Ethylene glycol (0.2%) 5-6 537 9 silica gel 2 Benzotriazole (0.1%) Adipic acid (0.2%) Ethylene glycol (0.4%) 3-4 553 10 Aluminum oxide 2 Benzotriazole (0.1%) Adipic acid (0.2%) Ethylene glycol (0.2%) 3-4 1139 11 Aluminum oxide 2 Benzotriazole (0.1%) Adipic acid (0.2%) 3-4 1802 12 silica gel 2 Benzotriazole (0.1%) Adipic acid (0.2%) 2-hydroxyacetic acid (0.2%) 3-4 613 13 Aluminum oxide 2 Benzotriazole (0.1%) Adipic acid (0.2%) 2-alcohol-acetic acid (0.2%) 3-4 1187

Comparing the results of Examples 1 to 7, it can be seen that the addition of ethylene glycol to the polishing slurry can prevent copper sagging.

Comparing the results of Examples 6 and 8, it can be seen that adding ethylene glycol to the polishing slurry with different pH values can prevent copper sinking.

Comparing the results of Examples 6 and 9, it can be seen that adding different concentrations of ethylene glycol to the polishing slurry can prevent copper sinking.

Comparing the results of Examples 3 and 6 and Examples 10 and 11, it can be seen that the addition of ethylene glycol is suitable for the abrasive slurry with silica gel and alumina as abrasive particles, and both can achieve the effect of preventing copper sagging.

Comparing the results of Examples 3 and 12 and 11 and 13, it can be seen that adding 2-alcohol-acetic acid to the polishing slurry can also prevent copper dishing.

Claims (17)

1. chemical and mechanical grinding fluid composition, it comprises the aqueous medium of 80-99.5 weight %; 0.1-25 the abrasive grains of weight %; 0.01-1 the corrosion inhibitor of weight %; And the chemical that is selected from two alcoholate and 2-hydroxycarboxylic acid thing and composition thereof of 0.01-1 weight %, wherein this two alcoholate has following structural formula:

Wherein, R ¹And R ²Be selected from H or C respectively ₁-C ₆Alkyl, and wherein this 2-hydroxycarboxylic acid thing has following structural formula:

Wherein, R is H or C ₁-C ₆Alkyl, and said composition pH value is 3-4 or 5-6.

2. composition as claimed in claim 1, wherein abrasive grains is selected from SiO ₂, Al ₂O ₃, ZrO ₂, CeO ₂, SiC, Fe ₂O ₃, TiO ₂, Si ₃N ₄And composition thereof.

3. composition as claimed in claim 1, it comprises the abrasive grains of 0.5-10 weight %.

4. composition as claimed in claim 3, it comprises the abrasive grains of 0.5-5.0 weight %.

5. composition as claimed in claim 1, wherein this two alcoholate is an ethylene glycol.

6. composition as claimed in claim 5, it comprises the ethylene glycol of 0.01-0.5 weight %.

7. as the composition of claim 5, it is the ethylene glycol that comprises 0.1-0.4 weight %.

8. as the composition of claim 1, wherein this 2-hydroxycarboxylic acid thing is the 2-oxyacetic acid.

9. as the composition of claim 8, it comprises the 2-oxyacetic acid of 0.01-0.5 weight %.

10. as the composition of claim 8, it comprises the 2-oxyacetic acid of 0.1-0.4 weight %.

11. as the composition of claim 1, wherein this corrosion inhibitor is the triazolam thing.

12. as the composition of claim 11, wherein this triazolam thing is a benzotriazole.

13. composition as claimed in claim 1, it further comprises the oxygenant of 0.1-5 weight %.

14. as the composition of claim 13, wherein this oxygenant is selected from H ₂O ₂, Fe (NO ₃) ₃, KIO ₃, CH ₃COOOH and KMnO ₄

15. as the composition of claim 14, wherein this oxygenant is H ₂O ₂

16. composition as claimed in claim 1, wherein this aqueous medium is a deionized water.

17. a method that is used for the polishing semiconductor wafers surface, it is included in uses on the crystal column surface as each chemical and mechanical grinding fluid composition of claim 1 to 16.