CN102850937A - Chemical mechanical polishing (CMP) liquid - Google Patents
Chemical mechanical polishing (CMP) liquid Download PDFInfo
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- CN102850937A CN102850937A CN 201110178411 CN201110178411A CN102850937A CN 102850937 A CN102850937 A CN 102850937A CN 201110178411 CN201110178411 CN 201110178411 CN 201110178411 A CN201110178411 A CN 201110178411A CN 102850937 A CN102850937 A CN 102850937A
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Abstract
A chemical mechanical polishing (CMP) liquid is composed of water, grinding agent with specific surface area range of 120-300 m<2>/g (measured via BET method), 0.1-0.2 wt% compound capable of generating silver ion, 0.1-0.3 wt% compound capable of generating sulfate ion, and peroxide. Under the premise of ensuring high polishing speed of tungsten, by optimizing specific surface area range of grinding agent, and mass percent of silver ion and sulfate ion, residual particles on silicon wafer surface of the polishing liquid can be reduced greatly, and production cost is also reduced.
Description
Technical field
The present invention relates to a kind of chemical mechanical polishing liquid, relate in particular to a kind of chemical mechanical polishing liquid for the polish tungsten material.
Background technology
Development along with semiconductor technology, and the continuous increase of large-scale integrated circuit interconnection layer, it is particularly crucial that the planarization of conductive layer and insulating medium layer becomes, wherein, by IBM Corporation twentieth century eighties pioneering chemically machinery polished (CMP) technology be considered to the effective means of present overall planarization.Chemically machinery polished (CMP) is a kind ofly to be combined by chemical action, mechanical effect and this two kinds of effects and realize the technology of planarization; It is usually by a grinding stage with polishing pad, and a grinding head that is used for carries chips forms.Wherein grinding head is fixed chip, and then the front with chip is pressed on the polishing pad, and when carrying out chemically machinery polished, grinding head moves or along the direction of motion the same with grinding stage rotation at the polishing pad Linear; Meanwhile, the slurries that contain abrasive are dripped on the polishing pad, and are tiled on the polishing pad because of centrifugation.Chip surface is realized overall planarization under the dual function of machinery and chemistry.
Main mechanism to metal level chemically machinery polished (CMP) is considered to: oxygenant is removed this layer oxide film machinery as the abrasive of representative take silicon-dioxide and aluminum oxide first with the oxidation on metal surface film forming, produces new metallic surface; The new metallic surface that produces is continued oxidized, these two kinds collaborative the carrying out of effect.
As the tungsten of one of chemically machinery polished (CMP) object, under high current density, anti-electronic migration ability is strong, and can form good ohmic contact with silicon, so can be used as filler metal and the diffusion impervious layer of contact hole and interlayer hole.
The at present chemically machinery polished (CMP) of tungsten, several different methods is arranged, as: the Tripotassium iron hexacyanide of the report such as F.B.Kaufman is used for the method (" Chemical Mechanical Polishing for Fabricating Patterned W Metal Features as Chip Interconnects " of tungsten CMP, Journal of the Electro chemical Society, Vol.138, No.11, in November, 1991), US Patent No. 5340370 disclosed a kind of formula of size for tungsten CMP (CMP), wherein contain the Tripotassium iron hexacyanide and silica abrasive, contain simultaneously the acetate as the pH buffer reagent.Because the Tripotassium iron hexacyanide is under UV-light or sun exposure, and in acidic medium, can decomposite the prussic acid of severe toxicity, thereby limit it and be widely used.
US Patent No. 5527423 disclosed metal level chemical mechanical polishing liquids, the disclosed method of polishing semiconductor wafer of US Patent No. 006008119A and US Patent No. 6284151 disclosed tungsten CMP slurries etc. all adopt Fe (NO
3)
3/ Al
2O
3System is used for tungsten CMP (CM P).This polishing body ties up to static etch rate (static etch rate) aspect and has advantage, but owing to adopt aluminum oxide as abrasive, product defects (defect) aspect exists significantly not enough.The iron nitrate of high density is so that the pH value of polishing fluid is strongly-acid simultaneously, and severe corrosion equipment simultaneously, generates iron rust, pollutes polishing pad.In addition, the conduct of the iron ion of high density is metal ion movably, has seriously reduced the reliability of semiconductor components and devices.
US Patent No. 5958288 disclosed metal CMP polishing compositions adopt iron nitrate as catalyzer, hydrogen peroxide is used as oxygenant, carry out tungsten CMP, it should be noted that, in this patent, mentioned multiple transition metal, significantly effectively only had ferro element by experiment confirm, actual implementation result and the scope that therefore should invent are very limited.Although the method decrease the consumption of iron nitrate because iron ion still exists, and the Fenton reaction occurs between the hydrogen peroxide, hydrogen peroxide can be rapidly and decomposition failure tempestuously, so the poor problem of this polishing fluid existence and stability.
US Patent No. 5980775 open metal CMP polishing slurries and US Patent No. 6068787 disclosed polishing slurries are on US Patent No. 5958288 bases, add organic acid and make stablizer, improved the rate of decomposition of hydrogen peroxide, but hydrogen peroxide decomposition speed is still higher, hydrogen peroxide concentration can reduce more than 10% in common two weeks, cause polishing velocity to descend, polishing fluid is decomposition failure gradually.
Because the static corrosion speed of tungsten is very fast in the system of iron and hydrogen peroxide, directly have influence on the yield of production, need further to add the static corrosion inhibitor of tungsten for this reason.Such as disclosed polishing composition and the disclosed polishing composition that comprises inhibitor of tungsten etching of CN1966594A that comprises inhibitor of tungsten etching of Chinese patent CN1326199C, the erosion inhibitor that has all added tungsten in the system of hydrogen peroxide and iron catalyst suppresses the corrosion of tungsten.The shortcoming of above-mentioned patent is: after adding inhibitor, can reduce the polishing velocity of tungsten.
Summary of the invention
The technical problem that the present invention solves provides a kind of chemical mechanical polishing liquid, when guaranteeing to be in the polishing velocity of very high tungsten, the scope of the specific surface area by optimizing abrasive, the mass percent of silver ions and the mass percent of sulfate ion, thus polishing fluid significantly reduced at the production cost of the residual particles of silicon chip surface and reduction polishing fluid.
Chemical mechanical polishing liquid of the present invention, it comprises: water, specific surface area (recording with BET specific surface area method of testing) scope are 120～300m
2The abrasive of/g, mass percent are that 0.1～0.2% the compound that can produce silver ions, mass percent are 0.1～0.3% can produce compound and the superoxide of sulfate ion.
Among the present invention, specific surface area (recording with B ET specific surface area method of testing) scope is 120～300m
2The abrasive of/g is selected from SiO
2
Among the present invention, specific surface area (recording with BET specific surface area method of testing) scope is 120～300m
2The quality percentage composition of the abrasive of/g is 0.1～10%, and is preferably 0.5～6%.
Among the present invention, the compound that can produce silver ions can be one or more in the soluble silver salt of Sulfuric acid disilver salt, Silver Nitrate, silver fluoride and/or silver perchlorate.
Among the present invention, the compound that can produce sulfate ion can be vitriol, goodly is chosen as in the nonmetallic vitriol one or more; Wherein, nonmetal vitriol is preferably ammonium sulfate.
Among the present invention, superoxide is preferably hydrogen peroxide, and its content is preferably mass percent 0.1～5%, and optimum content is mass percent 1～2%.
Polishing fluid of the present invention can also further contain pH adjusting agent; Preferably, polishing fluid pH value of the present invention is 0.5～5.
Among the present invention, chemical mechanical polishing liquid is used for the polishing to tungsten.
Agents useful for same of the present invention and raw material be commercially available getting all.
Positive progressive effect of the present invention is:
1) when guaranteeing to be in the polishing velocity of very high tungsten, the scope of the specific surface area by optimizing abrasive, the mass percent of silver ions and the mass percent of sulfate ion, thus polishing fluid significantly reduced at the production cost of the residual particles of silicon chip surface and reduction polishing fluid;
2) pollution of reduction environment alleviates the pressure of sewage disposal;
3) reduce the mass percent of each compound after, be conducive to improve the stability of polishing fluid after concentrated, further improve conveying efficiency, reduce transportation cost.
Embodiment
Be described in detail below by the chemical mechanical polishing liquid of specific embodiment to polish tungsten of the present invention, so that better understand the present invention, but following embodiment does not limit the scope of the invention.Each percentage composition is mass percent among the embodiment.
Embodiment 1～12
The chemical mechanical polishing liquid of polish tungsten of the present invention comprises Silver Nitrate (material of silver ions is provided), ammonium sulfate (material of sulfate ion is provided), hydrogen peroxide (hydrogen peroxide) and silica abrasive.Quality percentage composition and the pH value of each main ingredient see Table 1.
Each component mixes in deionized water, regulates the pH value of polishing fluid with pH adjusting agent.
Comparative Examples 1～16
Take silicon-dioxide as abrasive, hydrogen peroxide is oxygenant, the chemical mechanical polishing liquid of preparation Comparative Examples 1～16.
Wherein, Comparative Examples 1 does not add silver ions and sulfate ion, and Comparative Examples 2～16 adds Silver Nitrate on the basis of Comparative Examples 1 provides silver ions and ammonium sulfate that sulfate ion is provided.
Each component mixes in deionized water, adds pH adjusting agent and regulates the pH value, prepares the contrast polishing fluid.
Comparative Examples main ingredient mass percent and polishing fluid pH value see Table 2.
Table 1, chemical mechanical polishing liquid embodiment 1～12 of the present invention
The component proportion of table 2, Comparative Examples 1～16
Effect embodiment
The polishing fluid of preparing in above-described embodiment and the Comparative Examples is carried out respectively the chemically machinery polished of tungsten, and polishing effect is compared.Concrete contrast sees Table 3.
Polishing condition: polishing machine platform is Logitech (Britain) 1PM52 type, polytex polishing pad, 4cm * 4cm square wafer (Wafer), grinding pressure 4psi, 70 rev/mins of grinding stage rotating speeds, 150 rev/mins of grinding head rotation rotating speeds, polishing fluid rate of addition 100ml/ minute.
Table 3, the Comparative Examples 1～16 that is used for tungsten and silicon-dioxide polishing and the contrast of embodiment 1～12 polishing effect
| Tungsten polishing speed (A/min) | |
| Comparative Examples 1 | 436 |
| Comparative Examples 2 | 850 |
| Comparative Examples 3 | 1475 |
| Comparative Examples 4 | 2079 |
| Comparative Examples 5 | 2551 |
| Comparative Examples 6 | 3420 |
| Comparative Examples 7 | 3510 |
| Comparative Examples 8 | 1100 |
| Comparative Examples 9 | 2311 |
| Comparative Examples 10 | 3382 |
| Comparative Examples 11 | 3400 |
| Comparative Examples 12 | 3311 |
| Comparative Examples 13 | 3473 |
| Comparative Examples 14 | 3000 |
| Comparative Examples 15 | 3430 |
| Comparative Examples 16 | 1600 |
| Embodiment 1 | 3010 |
| Embodiment 2 | 3177 |
| Embodiment 3 | 2956 |
| Embodiment 4 | 3170 |
| Embodiment 5 | 3375 |
| Embodiment 6 | 3433 |
| Embodiment 7 | 3400 |
| Embodiment 8 | 2230 |
| Embodiment 9 | 2190 |
| Embodiment 10 | 3425 |
| Embodiment 11 | 2200 |
| Embodiment 12 | 1610 |
The different specific surface areas of table 4, abrasive polishing fluid after polishing compares at the residual particles number of silicon chip surface
Comparative Examples 1 shows: when only having abrasive and hydrogen peroxide to exist, the polishing velocity of tungsten is very low.
Comparative Examples 2～7, embodiment 1～2 and embodiment 6 compare rear discovery: when the content of abrasive identical, the mass percent of sulfate radical is identical, the mass percent of hydrogen peroxide is identical, in the identical situation of pH value, increase the mass percent of silver ions, the polishing velocity of tungsten increases, but continues to increase the mass percent of silver ions, and the polishing velocity of tungsten does not have the obviously trend of increase.As can be seen from the table, the mass percent of silver ions preferably in 0.1～0.2 scope, when guaranteeing the polishing velocity of very high tungsten, can significantly reduce the production cost of polishing fluid.
Comparative Examples 8～13, embodiment 3～6 compare rear discovery: when the content of abrasive identical, the mass percent of silver ions is identical, the mass percent of hydrogen peroxide is identical, in the identical situation of pH value, increase the mass percent of sulfate radical, the polishing velocity of tungsten increases, but continues to increase the mass percent of sulfate ion, and the polishing velocity of tungsten does not have the obviously trend of increase.As can be seen from the table, the mass percent of sulfate ion preferably in 0.1～0.3 scope, when guaranteeing the polishing velocity of very high tungsten, can significantly reduce the production cost of polishing fluid.
By the relatively discovery of table 4, when specific surface area (recording with the BET specific surface area method of testing) scope of abrasive is 120～300m
2The polishing fluid of/g can significantly reduce polishing fluid at the residual particles number of silicon chip surface.
Shown that by above data chemical mechanical polishing liquid of the present invention has the following advantages:
1) when guaranteeing to be in the polishing velocity of very high tungsten, the scope of the specific surface area by optimizing abrasive, the mass percent of silver ions and the mass percent of sulfate ion, thus polishing fluid significantly reduced at the production cost of the residual particles of silicon chip surface and reduction polishing fluid.
2) pollution of reduction environment alleviates the pressure of sewage disposal;
3) reduce the mass percent of each compound after, be conducive to improve the stability of polishing fluid after concentrated, further improve conveying efficiency, reduce transportation cost.
More than specific embodiments of the invention are described in detail, but it is just as example, the present invention is not restricted to specific embodiment described above.To those skilled in the art, any equivalent modifications that the present invention is carried out and substituting also all among category of the present invention.Therefore, not breaking away from impartial conversion and the modification of doing under the spirit and scope of the present invention, all should contain within the scope of the invention.
Claims (14)
1. chemical mechanical polishing liquid, comprise: water, specific surface area scope are 120～300m
2The abrasive of/g, mass percent are that 0.1～0.2% the compound that can produce silver ions, mass percent are 0.1～0.3% can produce compound and the superoxide of sulfate ion.
2. chemical mechanical polishing liquid as claimed in claim 1, it is characterized in that: described specific surface area scope is 120～300m
2The abrasive of/g is selected SiO
2
3. chemical mechanical polishing liquid as claimed in claim 1 or 2, it is characterized in that: described abrasive mass percent is 0.1～10%.
4. chemical mechanical polishing liquid as claimed in claim 3, it is characterized in that: described abrasive mass percent is 0.5～6%.
5. chemical mechanical polishing liquid as claimed in claim 1, it is characterized in that: the described compound that can produce silver ions is the soluble silver salt of Sulfuric acid disilver salt, Silver Nitrate, silver fluoride and/or silver perchlorate.
6. chemical mechanical polishing liquid as claimed in claim 1, it is characterized in that: the described compound that can produce sulfate ion is vitriol.
7. chemical mechanical polishing liquid as claimed in claim 6, it is characterized in that: described vitriol is nonmetal vitriol.
8. chemical mechanical polishing liquid as claimed in claim 7, it is characterized in that: described nonmetal vitriol is ammonium sulfate.
9. chemical mechanical polishing liquid as claimed in claim 1, it is characterized in that: described superoxide is hydrogen peroxide.
10. such as claim 1 or 9 described chemical mechanical polishing liquids, it is characterized in that: described superoxide mass percent is 0.1～5%.
11. chemical mechanical polishing liquid as claimed in claim 10 is characterized in that: described superoxide mass percent is 1～2%.
12. chemical mechanical polishing liquid as claimed in claim 1 is characterized in that: described chemical mechanical polishing liquid also comprises pH adjusting agent.
13. such as claim 1 or 12 described chemical mechanical polishing liquids, it is characterized in that: the pH value of described chemical mechanical polishing liquid is 0.5～5.
14. such as each described chemical mechanical polishing liquid of claim 1-13, it is characterized in that: described chemical mechanical polishing liquid is used for polish tungsten.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110178411 CN102850937A (en) | 2011-06-29 | 2011-06-29 | Chemical mechanical polishing (CMP) liquid |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110178411 CN102850937A (en) | 2011-06-29 | 2011-06-29 | Chemical mechanical polishing (CMP) liquid |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111378373A (en) * | 2018-12-28 | 2020-07-07 | 安集微电子（上海）有限公司 | Chemical mechanical polishing solution for polishing tungsten |
| CN115820128A (en) * | 2022-11-22 | 2023-03-21 | 深圳市永霖科技有限公司 | Chemical mechanical polishing solution for indium phosphide polishing and polishing process |
-
2011
- 2011-06-29 CN CN 201110178411 patent/CN102850937A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111378373A (en) * | 2018-12-28 | 2020-07-07 | 安集微电子（上海）有限公司 | Chemical mechanical polishing solution for polishing tungsten |
| CN115820128A (en) * | 2022-11-22 | 2023-03-21 | 深圳市永霖科技有限公司 | Chemical mechanical polishing solution for indium phosphide polishing and polishing process |
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Application publication date: 20130102 |