CN111378376A - Chemical mechanical polishing solution and application thereof - Google Patents
Chemical mechanical polishing solution and application thereof Download PDFInfo
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- CN111378376A CN111378376A CN201811635491.1A CN201811635491A CN111378376A CN 111378376 A CN111378376 A CN 111378376A CN 201811635491 A CN201811635491 A CN 201811635491A CN 111378376 A CN111378376 A CN 111378376A
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09G—POLISHING COMPOSITIONS; SKI WAXES
- C09G1/00—Polishing compositions
- C09G1/02—Polishing compositions containing abrasives or grinding agents
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Abstract
The invention provides a chemical mechanical polishing solution which comprises silicon dioxide grinding particles, a corrosion inhibitor, a complexing agent, an oxidizing agent and a phosphate surfactant. The polishing solution has the advantages that: 1) the polishing solution has high polishing rate to copper and low polishing rate to tantalum, thereby having higher copper/tantalum polishing rate selection ratio; 2) the polishing solution can improve the dishing depression of a copper wire and the erosion of a dielectric layer after polishing.
Description
Technical Field
The invention relates to the field of chemical mechanical polishing, in particular to a chemical mechanical polishing solution and application thereof.
Background
With the development of semiconductor technology and the miniaturization of electronic parts, copper is widely used in electronic element circuits as a material having good conductivity. Because the resistance of copper is small, the transfer speed of signals between transistors in a circuit can be accelerated, and the parasitic capacitance capability and the electromigration sensitivity are smaller. These electrical advantages have led to copper with good prospects for the development of semiconductor technology.
However, during the fabrication of copper integrated circuits, it has been found that copper migrates or diffuses into the transistor areas of the integrated circuits, thereby adversely affecting the performance of the transistors of the semiconductor, and therefore copper interconnects can only be fabricated in a damascene process, i.e.: and forming a groove in the first layer, filling the groove with a copper barrier layer and copper, and forming a metal wire to cover the dielectric layer. The excess copper/copper barrier layer on the dielectric layer is then removed by chemical mechanical polishing, leaving a single interconnect line in the trench. The copper chemical mechanical polishing process is generally divided into 3 steps: step 1, removing a large amount of copper on the surface of the substrate by using a high down pressure at a high and efficient polishing rate and leaving copper with a certain thickness, step 2, removing the residual metal copper by using a low polishing rate and stopping on the barrier layer, and step 3, removing the barrier layer, a part of the dielectric layer and the metal copper by using a barrier layer polishing solution to realize planarization.
In the copper polishing process, on one hand, redundant copper on the barrier layer is removed as soon as possible, and on the other hand, the dishing of the polished copper wire is reduced as much as possible. The metal layer is partially recessed above the copper lines prior to copper polishing. During polishing, copper on the dielectric material is easy to remove under the main pressure (higher), and the polishing pressure of copper at the concave part is lower than the main pressure, so that the copper polishing speed is low. As the polishing progresses, the height difference of the copper is gradually reduced to achieve planarization. However, if the chemical action of the copper polishing solution is too strong and the static etch rate is too high during polishing, the passivation film of copper is easily removed even at a low pressure (e.g., at the dishing of the copper line), resulting in a decrease in planarization efficiency and an increase in dishing after polishing.
With the development of integrated circuits, on the one hand, in the conventional Integrated Circuit (IC) industry, in order to improve the integration level, reduce the power consumption, and shorten the delay time, the line width is narrower and narrower, the dielectric layer is made of a low dielectric (low-k) material with lower mechanical strength, the number of layers of the wiring is also greater and greater, and the requirement on the copper chemical mechanical polishing is also higher and higher in order to ensure the performance and stability of the integrated circuit. It is required to reduce polishing pressure, improve the flatness of the copper wire surface, and control surface defects while ensuring the polishing rate of copper. On the other hand, due to physical limitations, line widths cannot be infinitely reduced, and the semiconductor industry is not simply relying on integrating more devices on a single chip to improve performance, but is turning to multi-chip packaging.
Through Silicon Via (TSV) technology has gained wide acceptance in the industry as a new technology for achieving interconnection between chips by making vertical conduction between chips and between wafers. The TSV can enable the stacking density of the chips in the three-dimensional direction to be the largest, the overall size to be the smallest, and the chip speed and the low power consumption performance to be greatly improved. The conventional IC process is combined to form a copper via penetrating through a silicon substrate, that is, copper is filled in a TSV opening to achieve conduction, and the excess copper after filling needs to be removed by chemical mechanical polishing to achieve planarization. Unlike the conventional IC industry, the excess copper on the filled back surface is typically several to tens of microns thick due to the deep through-silicon vias. In order to remove the excess copper quickly and stop polishing at the barrier layer, the polishing solution is required to have a high copper polishing rate and a high copper/barrier layer polishing rate selectivity, and the polished wafer surface has small Dishing (disching) of copper lines and dielectric layer Erosion (Erosion) and good flatness. The existing polishing solution can not meet the requirements at the same time.
Disclosure of Invention
In order to solve the above problems, the present invention provides a chemical mechanical polishing solution. The chemical mechanical polishing solution has higher copper polishing rate and lower tantalum polishing rate by compounding the phosphate surfactant and the corrosion inhibitor, thereby having higher copper/tantalum polishing rate selection ratio. Meanwhile, the chemical mechanical polishing solution can improve the dishing depression of the polished copper wire and the erosion of the dielectric layer.
Specifically, the invention provides a chemical mechanical polishing solution which comprises silicon dioxide abrasive particles, a corrosion inhibitor, a complexing agent, an oxidizing agent and a phosphate surfactant.
Preferably, the silica abrasive particles have an average particle size of 60 to 140 nm.
Preferably, the silica abrasive particles have an average particle size of 80 to 120 nm.
Preferably, the silica abrasive particles have a particle size distribution index of 0.1 to 0.6.
Preferably, the content of the silica abrasive particles is 0.05-2% by mass.
Preferably, the content of the silica abrasive particles is 0.1-1% by mass.
Preferably, the phosphate ester surfactant is
Or
One or more of them.
Preferably, X ═ RO, RO- (CH)2CH2O) n, or RCOO- (CH)2CH2O) n, R is C8-C22 alkyl or alkylbenzene, glyceryl; n is 3-30, M is H, K, NH4，Na。
Preferably, the phosphate ester surfactant accounts for 0.001-1.0% by mass.
Preferably, the phosphate ester surfactant accounts for 0.005-0.5% by mass.
Preferably, the complexing agent is selected from one or more of glycine, alanine, valine, leucine, proline, phenylalanine, tyrosine, tryptophan, lysine, arginine, histidine, serine, aspartic acid, glutamic acid, asparagine, glutamine, nitrilotriacetic acid, ethylenediaminetetraacetic acid, cyclohexanediaminetetraacetic acid, ethylenediamine disuccinic acid, diethylenetriaminepentaacetic acid, and triethylenetetraminehexaacetic acid.
Preferably, the content of the complexing agent is 0.1-5% by mass.
Preferably, the content of the complexing agent is 0.5-3% by mass.
Preferably, the corrosion inhibitor comprises one or more of 1, 2, 4-triazole, 3-amino-1, 2, 4-triazole, 4-amino-1, 2, 4-triazole, 3, 5-diamino-1, 2, 4-triazole, 5-carboxyl-3-amino-1, 2, 4-triazole, 3-amino-5-mercapto-1, 2, 4-triazole, 5-acetic acid-1H-tetrazole, 5-methyltetrazole and 5-amino-1H-tetrazole.
Preferably, the content of the corrosion inhibitor is 0.001-2% by mass.
Preferably, the content of the corrosion inhibitor is 0.005-1% by mass.
Preferably, the oxidizing agent is hydrogen peroxide.
Preferably, the content of the oxidant is 0.05-5% by mass.
Preferably, the content of the oxidant is 0.1-3% by mass.
Preferably, the pH value of the chemical mechanical polishing solution is 5-8.
Another aspect of the present invention is the use of the above-described chemical mechanical polishing slurry in the polishing of copper metal.
The polishing solution of the invention can also comprise common additives in the chemical mechanical polishing solution, such as a pH regulator, a viscosity regulator, an antifoaming agent and the like.
Compared with the prior art, the invention has the advantages that: 1) the polishing solution has higher copper polishing rate and lower tantalum polishing rate, thereby having higher copper/tantalum polishing rate selectivity ratio; 2) the polishing solution can improve the dishing depression of a copper wire and the erosion of a dielectric layer after polishing.
Detailed Description
The advantages of the present invention are further illustrated by the following specific examples, but the scope of the present invention is not limited to the following examples.
Table 1 shows the components and contents of the polishing solutions of examples 1 to 27 of the present invention. According to the formula given in the table, the components except the oxidant are uniformly mixed, and water is used for complementing the mass percent to 100 percent. With KOH or HNO3Adjusting to the required pH value. Adding oxidant before use, and mixing well.
TABLE 1 polishing solutions of inventive examples 1 to 27
Table 2 shows examples 28 to 37 and comparative examples 1 to 7 of the chemical mechanical polishing liquid of the present invention, in which the components other than the oxidizing agent were mixed uniformly in the formulation shown in the table, and water was added to make up the mass% to 100%. With KOH or HNO3Adjusting to the required pH value. Adding oxidant before use, and mixing well.
TABLE 2 polishing liquid Components of comparative examples 1 to 7 and examples 28 to 37
Using the polishing liquids of comparative examples 1 to 7 and inventive examples 28 to 37, the polishing was carried out on the bare copper (Cu) and tantalum (Ta) under the following conditions. The specific polishing conditions are as follows: cu polishing pressures of 1.5psi and 2.0psi, tantalum polishing pressure of 1.5 psi; the rotation speed of the polishing disk and the polishing head is 73/67rpm, the polishing pad IC1010 and the flow rate of the polishing solution is 350mL/min, the polishing machine is 12' Reflexion LK, and the polishing time is 1 min. The polishing rates for copper/tantalum were measured for each example and the polishing rate selectivity was calculated for both, and the results are shown in Table 3.
The copper wafer containing the pattern was polished using the comparative polishing liquid and the polishing liquid of the present invention under the following conditions. Polishing conditions: the rotation speed of the polishing disk and the polishing head is 73/67rpm, the polishing pad IC1010, the flow rate of the polishing solution is 350ml/min, and the polishing machine is 12' Reflexion LK. The patterned copper wafer was polished on polishing disk 1 with a down force of 2psi to a residual copper level
The residual copper was then removed by applying a down force of 1.5psi to the polishing pad 2. The Dishing values (Dishing) and dielectric Erosion values (Erosion) of the 5um/1um (copper line/dielectric line width) copper line array regions on the patterned copper wafers were measured using an XE-300P atomic force microscope and are given in Table 3
TABLE 3 polishing Effect of the polishing solutions of comparative examples 1 to 7 and examples 28 to 37
As can be seen from Table 3, the polishing solutions of the examples of the present invention not only have a higher copper/tantalum polishing rate selectivity, but also have less dishing and dielectric erosion of copper wires and greatly improved surface morphology after polishing with the polishing solutions of the present invention. The polishing solution of comparative example 1 contains only abrasive grains, a complexing agent and an oxidizing agent, and has high polishing rates for copper and tantalum, so that the polishing rate selectivity for copper/tantalum is low; the polishing solution of the comparative example 2 is added with the corrosion inhibitor on the basis of the polishing solution of the comparative example 1, so that the polishing rate of tantalum is reduced, and the polishing rate selection ratio of the polishing solution to copper/tantalum is improved to a certain extent. However, the polishing rate selectivity of the polishing solution of comparative example 2 to copper/tantalum is still not high enough to satisfy the polishing requirement when tantalum is used as a barrier layer, and the dishing and dielectric erosion of the copper wire after polishing with the polishing solution of comparative example 2 are high.
From comparative examples 3 to 4 and example 28 it can be seen that: after the silicon dioxide grinding materials with different particle sizes are added, the particle size and the distribution of the grinding materials have obvious influence on the removal rate of copper, and when the particle size of the silicon dioxide grinding materials is smaller and the particle size distribution strength is wider or the particle size is larger and the particle size distribution strength is narrower, the removal rate of copper is lower. When the particle size and the particle size distribution strength of the silicon dioxide abrasive are within a certain range, copper has a high polishing rate, and the combination of the phosphate surfactant and the azole corrosion inhibitor can well inhibit the polishing rate of tantalum, so that the copper/tantalum polishing selection ratio is improved, and the butterfly-shaped depression and the dielectric layer erosion degree of a copper wire can be well improved when the high copper/tantalum polishing selection ratio is obtained.
Compared with the embodiment 28 of the invention, the combination of azole corrosion inhibitor without benzene ring and phosphate ester surfactant is added in the comparative examples 5 and 6, but the pH value of the comparative example 5 is too low, the removal rate of copper and tantalum is higher, and the dishing of the copper wire and the erosion of the dielectric layer are larger. The pH value of comparative example 6 was too high, which resulted in a greatly reduced copper removal rate and an ineffective copper removal. Meanwhile, in comparison with the components of example 28 and comparative example 7, it was found that the combination of benzotriazole, which is an azole corrosion inhibitor having a benzene ring, and a phosphate-based surfactant, although the removal rate of tantalum was reduced, greatly suppressed the removal rate of copper, and copper could not be effectively removed.
According to the polishing solution provided by the embodiment of the invention, by selecting the grinding particles with a proper particle size range and particle size distribution index and adding the combination of the azole corrosion inhibitor and the phosphate surfactant without benzene ring, the high removal rate of copper is maintained, the removal rate of the tantalum barrier layer is reduced, and the effect of improving the polishing selection ratio of the polishing solution to the copper and tantalum barrier layers is realized; the polishing method is used for polishing the wafer, can improve the disc-shaped recess of the polished copper wire and the erosion of the dielectric layer, and has no copper residues, corrosion and other defects after polishing.
The embodiments of the present invention have been described in detail, but the embodiments are merely examples, and the present invention is not limited to the embodiments described above. Any equivalent modifications and substitutions to those skilled in the art are also within the scope of the present invention. Accordingly, equivalent changes and modifications made without departing from the spirit and scope of the present invention should be covered by the present invention.
Claims (20)
1. A chemical mechanical polishing solution comprises silicon dioxide abrasive particles, a corrosion inhibitor, a complexing agent, an oxidizing agent and a phosphate surfactant.
2. The chemical mechanical polishing solution according to claim 1,
the silica abrasive particles have an average particle size of 60 to 140 nm.
3. The chemical mechanical polishing solution according to claim 2,
the silica abrasive particles have an average particle size of 80 to 120 nm.
4. The chemical mechanical polishing solution according to claim 1,
the silica abrasive particles have a particle size distribution index of 0.1 to 0.6.
5. The chemical mechanical polishing solution according to claim 1,
the content of the silicon dioxide grinding particles is 0.05-2% by mass.
6. The chemical mechanical polishing solution according to claim 5,
the content of the silicon dioxide grinding particles is 0.1-1% by mass.
7. The chemical mechanical polishing solution according to claim 1,
the phosphate ester surfactant has the following general formula:
or
Wherein X is RO, RO- (CH)2CH2O) n, or RCOO- (CH)2CH2O) n, R is C8-C22 alkyl or alkylbenzene, glyceryl; n is 3-30, M is H, K, NH4，Na。
8. The chemical mechanical polishing solution according to claim 1,
the phosphate ester surfactant accounts for 0.001-1.0% by mass.
9. The chemical mechanical polishing solution according to claim 8,
the phosphate ester surfactant accounts for 0.005-0.5% by mass.
10. The chemical mechanical polishing solution according to claim 1,
the complexing agent is selected from one or more of glycine, alanine, valine, leucine, proline, phenylalanine, tyrosine, tryptophan, lysine, arginine, histidine, serine, aspartic acid, glutamic acid, asparagine, glutamine, nitrilotriacetic acid, ethylene diamine tetraacetic acid, cyclohexanediamine tetraacetic acid, ethylenediamine disuccinic acid, diethylenetriamine pentaacetic acid and triethylene-tetramine hexaacetic acid.
11. The chemical mechanical polishing solution according to claim 1,
the mass percentage content of the complexing agent is 0.1-5%.
12. The chemical mechanical polishing solution according to claim 11,
the mass percentage content of the complexing agent is 0.5% -3%.
13. The chemical mechanical polishing solution according to claim 1,
the corrosion inhibitor comprises one or more of 1, 2, 4-triazole, 3-amino-1, 2, 4-triazole, 4-amino-1, 2, 4-triazole, 3, 5-diamino-1, 2, 4-triazole, 5-carboxyl-3-amino-1, 2, 4-triazole, 3-amino-5-mercapto-1, 2, 4-triazole, 5-acetic acid-1H-tetrazole, 5-methyltetrazole and 5-amino-1H-tetrazole.
14. The chemical mechanical polishing solution according to claim 1,
the content of the corrosion inhibitor is 0.001-2% by mass.
15. The chemical mechanical polishing solution according to claim 14,
the content of the corrosion inhibitor is 0.005-1% by mass.
16. The chemical mechanical polishing solution according to claim 1,
the oxidant is hydrogen peroxide.
17. The chemical mechanical polishing solution according to claim 1,
the mass percentage content of the oxidant is 0.05% -5%.
18. The chemical mechanical polishing solution according to claim 17,
the mass percentage content of the oxidant is 0.1% -3%.
19. The chemical mechanical polishing solution according to claim 1,
the pH value of the chemical mechanical polishing solution is 5-8.
20. Use of the chemical mechanical polishing liquid according to claims 1-19 in copper polishing.
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| CN201811635491.1A CN111378376A (en) | 2018-12-29 | 2018-12-29 | Chemical mechanical polishing solution and application thereof |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103160207A (en) * | 2011-12-16 | 2013-06-19 | 安集微电子（上海）有限公司 | Metal chemico-mechanical polishing sizing agent and application thereof |
| CN103866326A (en) * | 2012-12-10 | 2014-06-18 | 安集微电子（上海）有限公司 | Chemo-mechanical polishing slurry for metal, and its application |
| CN106929858A (en) * | 2015-12-31 | 2017-07-07 | 安集微电子科技(上海)有限公司 | Chemical mechanical polishing of metals slurry |
| CN108250978A (en) * | 2016-12-28 | 2018-07-06 | 安集微电子科技（上海）股份有限公司 | A kind of chemical mechanical polishing liquid and its application |
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- 2018-12-29 CN CN201811635491.1A patent/CN111378376A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103160207A (en) * | 2011-12-16 | 2013-06-19 | 安集微电子（上海）有限公司 | Metal chemico-mechanical polishing sizing agent and application thereof |
| CN103866326A (en) * | 2012-12-10 | 2014-06-18 | 安集微电子（上海）有限公司 | Chemo-mechanical polishing slurry for metal, and its application |
| CN106929858A (en) * | 2015-12-31 | 2017-07-07 | 安集微电子科技(上海)有限公司 | Chemical mechanical polishing of metals slurry |
| CN108250978A (en) * | 2016-12-28 | 2018-07-06 | 安集微电子科技（上海）股份有限公司 | A kind of chemical mechanical polishing liquid and its application |
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