TWI490290B - Chemical mechanical polishing solution - Google Patents

Description

Chemical mechanical polishing fluid

The present invention relates to a chemical mechanical polishing liquid, and in particular to a chemical mechanical polishing liquid containing abrasive particles, an oxidizing agent, a polyhydroxy compound, organic hydrazine and water.

TSV technology (Through-Silicon-Via) is the latest technology to achieve interconnection between wafers by making vertical conduction between wafer and wafer, between wafer and wafer. Unlike previous IC package bonding and bump overlay technology, TSV has the advantage of maximizing the density of stacked wafers in the three-dimensional direction, minimizing the size of the interconnect, and improving interconnect speed for improved wafer speed and low power consumption.

In the TSV technology, backside thinning requires polishing at the same time, and has a very high polishing speed for both tantalum and copper materials.

Polishing of the crucible is usually carried out under alkaline conditions, and a higher polishing speed can be obtained. E.g:

US2002032987 discloses a polishing liquid using an alcoholamine as an additive to increase the removal rate of polysilicon, wherein the additive is preferably 2-(dimethylamino)-2-methyl-1-propanol.

US 2002151252 discloses a polishing fluid comprising a complexing agent having a plurality of carboxylic acid structures for increasing the rate of polysilicon removal, wherein the preferred complexing agents are EDTA (ethylenediaminetetraacetic acid) and DTPA (diethyltriaminepentaacetic acid). .

EP1072662 discloses a polishing liquid containing an organic substance in which deuterium forms a delocalized structure for electrons and double bonds to increase the removal rate of polysilicon. Preferably, the compound is a compound of a terpenoid and a salt thereof.

US2006014390 discloses a polishing fluid for increasing the removal rate of polysilicon comprising from 4.25% to 18.5% by weight of abrasive and from 0.05% to 1.5% by weight of additives. The additive is mainly selected from the group consisting of quaternary ammonium salts, quaternary amines and ethanolamines. Further, the polishing liquid further contains a nonionic surfactant such as a homopolymer or a copolymerization product of ethylene glycol or propylene glycol.

CN101497765A significantly improves the polishing speed of tantalum by utilizing the synergistic action of biguanide and azole materials.

The polishing of copper is usually carried out under acidic conditions, using a high oxidation potential of an oxidizing agent (hydrogen peroxide) under acidic conditions, and copper is easily coordinated and dissolved under acidic conditions to achieve a high polishing rate. E.g:

CN1705725A discloses a polishing liquid for polishing a copper metal surface, the polishing liquid being between 2.5 and 4.0, and removing the surface of the copper metal by the action of an oxidizing agent (hydrogen peroxide, etc.), a chelating agent and a passivating agent.

CN1787895A discloses a CMP composition comprising a fluid agent together with an oxidizing agent, a chelating agent, an inhibitor, an abrasive, and a solvent. Under acidic conditions, such a CMP composition advantageously increases the material selectivity in the CMP process and can be used to polish the surface of a copper component on a semiconductor substrate without creating depressions or other unfavorable planarization in the polished copper. defect.

CN01818940A discloses that a copper polishing slurry can be formed by further combining with an oxidizing agent such as hydrogen peroxide, and/or a corrosion inhibitor such as benzotriazole, increasing the copper removal rate. This higher polishing rate is achieved while maintaining local pH stability and significantly reducing overall and localized corrosion.

Polishing of copper is sometimes carried out under alkaline conditions, for example: CN1644640A discloses an aqueous composition for polishing copper under alkaline conditions, the composition comprising 0.001% to 6% by weight of non-ferrous metal Inhibitor, 0.05% to 10% by weight of the metal complexing agent, 0.01% to 25% by weight of copper remover for accelerating copper removal, 0.5% to 40% by weight of abrasive, etc. The copper removal rate is increased by the interaction of the copper remover imidazole and BTA.

CN1398938A discloses a chemical mechanical global planarization polishing liquid for multi-layer integrated circuit copper wiring, which is used for increasing the removal rate of copper. The composition of the polishing liquid is as follows: the weight percentage of the abrasive is 18% to 50%, and the weight of the chelating agent The percentage is from 0.1% to 10%, the weight percent of the complexing agent is from 0.005% to 25%, the weight percent of the active agent is from 0.1% to 10%, the weight percent of the oxidizing agent is from 1% to 20%, and deionized water.

In the prior art, polishing under acidic conditions, although a high copper polishing speed can be obtained, the polishing speed for tantalum is generally low. The reason is that under acidic conditions, the polishing speed of bismuth is generally lower than that under alkaline conditions. In addition, if an oxidizing agent is added under acidic conditions, the oxidizing agent oxidizes the surface of elemental cerium to cerium oxide, compared with cerium. Ceria is more difficult to remove.

Polishing under alkaline conditions, if no oxidizing agent is applied, although a very high polishing speed can be obtained, the polishing speed for copper is generally low. The reason is that copper needs to be oxidized before it is easily removed. However, if an oxidizing agent is added, similar to that under acidic conditions, the oxidizing agent oxidizes the surface of the elemental cerium to cerium oxide, which is more difficult to remove. In addition, under alkaline conditions, oxidants such as hydrogen peroxide are very unstable and will rapidly decompose and fail.

The specific oxidizing agent and polyhydroxy compound of the present invention can significantly improve the polishing speed of copper in an alkaline polishing environment while increasing the polishing speed of the crucible.

The technical problem solved by the invention is that the polishing rate of copper under alkaline conditions is significantly improved by adding a specific oxidizing agent and a polyhydroxy compound, so that the polishing speed of bismuth and copper can be "simultaneously" significantly improved under alkaline polishing conditions. problem.

The chemical mechanical polishing liquid of the present invention contains abrasive particles, an oxidizing agent, a polyhydroxy compound, an organic hydrazine and water.

In the present invention, the abrasive particles are selected from one or more of SiO2, Al2O3, ZrO2, CeO2, SiC, Fe2O3, TiO2, and/or Si3N4. It is preferably SiO2.

In the present invention, the abrasive particles have a mass percentage of 2 to 25%, preferably 5 to 15%.

In the present invention, the oxidizing agent is selected from one or more of the group consisting of perchlorate, nitrate, iodate, monopersulfate and/or 3-nitrobenzenesulfonate. The iodate is a potassium salt, and the nitrate is an ammonium nitrate salt and/or a potassium salt.

In the present invention, the oxidizing agent has a mass percentage of 1 to 3%.

In the present invention, the polyhydroxy compound is a saccharide. The saccharide is glucose and/or lactose, the organic hydrazine is an organic amine and/or a quaternary ammonium cerium, the organic amine is ethylenediamine and/or piperazine, and the quaternary ammonium cerium is a tetramethyl Based on ammonium hydroxide.

In the present invention, the organic germanium has a mass percentage of 1 to 10%.

In the present invention, a pH adjuster is contained. The chemical mechanical polishing liquid of the present invention has a pH of 10.0 to 12.0.

The positive progress of the present invention is that the polishing speed of copper under alkaline conditions is remarkably improved, so that the polishing speed of tantalum and copper is significantly improved at the same time under alkaline polishing conditions.

The invention is further illustrated by the following examples.

Preparation example

The invention is further illustrated by the following examples, but the invention is not limited thereto. In the following examples, the percentages are all percentages by mass.

Table 1 shows the formulations of the chemical mechanical polishing liquids of the present invention in Examples 1 to 25 and Comparative Examples 1 to 3, according to the components listed in Table 1 and their contents, uniformly mixed in deionized water, using a pH adjuster A chemical mechanical polishing solution can be prepared by adjusting to the desired pH.

Effect embodiment

Polishing conditions: Polishing machine is Logitech (UK) 1PM52 type, polytex polishing pad, 4cm × 4cm square wafer (Wafer), grinding pressure 3psi, grinding table rotation speed 70rev / min, grinding head rotation speed 150 rev / min, polishing The droplet acceleration is 100 ml/min.

From the data of Comparative Examples 1-3, it was found that the removal rates of copper and bismuth were very low in the presence of only the abrasive.

From the data of Examples 1-2 and Comparative Example 1, it was found that the removal rate of copper and cerium was significantly improved after the addition of our specific oxidizing agent and polyhydroxy compound at the same abrasive concentration.

From the data of Examples 3-5 and Comparative Example 2, it was found that the removal rate of copper and cerium was significantly improved after the addition of our specific oxidizing agent and polyhydroxy compound at the same abrasive concentration.

From the data of Examples 6-11 and Comparative Example 3, it was found that the removal rate of copper and cerium was significantly increased after the addition of our specific oxidizing agent and polyhydroxy compound at the same abrasive concentration.

From the data of Example 7 and Example 12, it was found that, by changing the concentration of the abrasive only when the oxidizing agent and the polyhydroxy compound were unchanged, it was found that increasing the concentration of the abrasive did not significantly reduce the removal rate of copper and bismuth. The improvement of the embodiment 7 is better than that of the embodiment 12.

It can be seen from the data of Examples 10 and 11 that the presence of a polyhydroxy compound can increase the removal rate of copper.

From the data of Example 6 and Example 9, it can be found that by increasing the amount of the oxidizing agent, the removal rates of copper and cerium are remarkably improved.

Claims (13)

A chemical mechanical polishing liquid for improving the polishing rate of copper and bismuth, the chemical mechanical polishing liquid containing abrasive particles, an oxidizing agent, a polyhydroxy compound, an organic hydrazine and water, the polyhydroxy compound being a saccharide, the saccharide For glucose and / or lactose. According to the application of claim 1, the abrasive particles are selected from one of SiO ₂ , Al ₂ O ₃ , ZrO ₂ , CeO ₂ , SiC, Fe ₂ O ₃ , TiO ₂ and/or Si ₃ N ₄ or A variety. According to the application of claim 1, the abrasive particles have a mass percentage of 2 to 25%. According to the application of claim 1, the oxidizing agent is selected from one or more of the group consisting of perchlorate, nitrate, iodate, monopersulfate and/or 3-nitrobenzenesulfonate. According to the application of claim 4, the iodate is a potassium salt. According to the application of claim 4, the nitrate is an ammonium nitrate salt and/or a potassium salt. According to the application of claim 1, the oxidizing agent has a mass percentage of 1 to 3%. According to the application of claim 1, the organic hydrazine is an organic amine and/or a quaternary ammonium hydrazine. According to the application of claim 8, the organic amine is ethylenediamine and/or pyridazine. According to the application of claim 8, the quaternary ammonium hydrazine is tetramethylammonium hydroxide. According to the application of claim 1, the organic germanium has a mass percentage of 1 to 10%. According to the application described in claim 1, a pH adjuster is contained. According to the application described in claim 1, the pH is from 10.0 to 12.0.