CN1546627A - Novel cleaning solution for the stripping of silicon nitride film in wet method - Google Patents
Novel cleaning solution for the stripping of silicon nitride film in wet method Download PDFInfo
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- CN1546627A CN1546627A CNA2003101094597A CN200310109459A CN1546627A CN 1546627 A CN1546627 A CN 1546627A CN A2003101094597 A CNA2003101094597 A CN A2003101094597A CN 200310109459 A CN200310109459 A CN 200310109459A CN 1546627 A CN1546627 A CN 1546627A
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Abstract
The invention discloses a novel cleaning solution for the stripping of silicon nitride film in wet method which comprises, stripping-off silicon nitride film with phosphorus acid method, employing cleaning fluid consisting ammonia, hydroperoxide, ultra-pure water, TMAH and CDTA of right proportion to carry out purification through megacoustic disturbance technique, thus removing surface particles and remained phosphoric impurity stains.
Description
Technical field
The invention belongs to unicircuit (IC) manufacturing process technology field, be specifically related to a kind of new cleaning solution prescription solution silicon nitride wet method and peel off in-problem method.
Background technology
The device performance of unicircuit, reliability and silicon circuit finished product rate are subjected to remaining in silicon chip or device surface chemical reagent impurity and granule foreign and have a strong impact on.Because semiconductor surface and submicron-scale device feature extreme sensitivity are cleaned effective technology even are seemed more important than cleaning before behind initially cleaning of silicon chip, oxidation and the formation figure.Therefore, super cleaning silicon wafer surface preparation is in super large-scale integration (VLSI) silicon circuit is produced, and for example 64-and 256M DRAM device have become one of gordian technique." super cleaning " can be defined as the term of silicon face impurity atom and granule density, and ben is that total in general metallic impurity should be less than 10
10Atom/cm
2Greater than 0.1 micron particle, should be less than 0.1/cm
2, that is to say diameter is less than 31 particles for the 200mm silicon chip.In fact these very low amount of impurities make us unthinkable! And these are strictly regulated and just are based on the following fact: the entire device quality as mentioned above, is influenced by trace impurity seriously.Hundreds of each step of processing step all may cause contamination in advanced silicon integrated circuit manufacturing processed.For example for 64 and 256MDRAM or be equal to the integration density circuit in the whole production manufacturing processed, nearly 60 to 75 steps of matting clean, and account for 15% of total manufacturing technology steps.
Organic and inorganic and particulate contamination on the silicon chip surface normally is incorporated into silicon chip surface with chemistry or physical adsorption way or is embedded in the silicon chip surface autoxidation film.These contamination impurity and particulate contamination can have a strong impact on performance, yield rate and the reliability of device.Experiment shows have the substandard products above 50% to cause owing to cleaning not little at once contamination, thereby make the ultra-clean surface preparation technology become to make the key process technology of extensive (LSI) and ultra-large (VLSI) unicircuit (IC).So-called ultra-clean surface requires promptly that silicon chip surface does not have particulate contamination, organic pollutant, metal contamination thing, no natural oxide, hydrogen terminal or complete ultra-thin chemical oxide, surface microroughness will be little etc. fully.According to ITRSRoadmap in 2000, be example with 0.18 micron VLSI CMOS IC process for making, preceding road technology integrated to the cleaning technical requirements referring to shown in the Table I.
Table I: the part of ITRS Roadmap in 2000
| Technology generation | 180nm |
| Granule number is (individual/cm 2) | 0.325 |
| Granular size (nm) | 82.5 |
| Surface metal concentration (atom/cm 2) | 7E9 |
| Movable concentration of metal ions (atom/cm 2) | 4.25E10 |
| Organic/polymeric impurities (carbon atom/cm 2) | 6.6E13 |
| Surface microroughness (nm) | 0.14 |
This shows, must remove effectively during cleaning the surface organic and inorganic pollutant, and don't the erosion and destroy silicon chip surface or cause surface roughening.
What generally adopt in the world semiconductor unicircuit production at present is that Werner Kern is applied in the production of RCA silicon semiconductor device in the nineteen sixty-five research and development, and delivers RCA standard cleaning method in 1970.Afterwards, people find that in the semiconductor integrated circuit production process there are many shortcomings in RCA standard cleaning method.Therefore, RCA standard cleaning method constantly is improved and is perfect.
The conventional clean processing sequence is: at first use sulfuric acid (H
2SO
4)/hydrogen peroxide (H
2O
2), being called for short SPM, ratio is the 3/1-10/1 mixing solutions, cleans under high temperature 90-140 ℃ condition, main purpose is to remove organism and/or photoresist material.Then need hot water to carry out rinsing, remove resistates.Second step adopted 1-2% diluted hydrofluoric acid (dHF) to remove zone of oxidation.Adopt typical R CA cleaning then, promptly a standard cleaning solution (SC1) cleans, and after the high purity water rinsing, and then uses No. two standard cleaning solution (SC2) to clean, and carries out rinsing and drying at last.
Adopt SPM to clean following shortcoming is arranged: use a large amount of sulfuric acid and hydrogen peroxide, need a large amount of hot water to carry out rinsing repeatedly and remove various resistatess, yet experimental results show that from the teeth outwards still has " sulphur " resistates.The sulfuric acid waste treatment is another shortcoming.Otherwise serious environment pollution.Several new methods, for example sulfuric acid (H have been developed at present
2SO
4)/ozone (O
3) be called for short SOM, and ozone (O
3)/DI water replaces SPM.These two kinds of cleaning solutions only need several ppm (1,000,000/) ozone.Particularly ozone/DI glassware for drinking water has or not sulphur production, does not have environmental pollution, and advantage such as reduce production costs simultaneously greatly.
APM has been widely used in the manufacturing of silicon semiconductor unicircuit.A large amount of experiments have proved that APM has excellent particle removal ability, as shown in Figure 1.Yet APM mixing cleaning solution does not obtain fine optimization for clean metal impurity.As everybody knows when there are metallic impurity in rinse bath, owing to metallic impurity catalysis decomposing hydrogen dioxide solution causes cleaning solution minimizing in work-ing life, as shown in Figure 2.Have been found that particularly the hazardness that exists of metallic iron and a little copper is very large.And in cleaning process, have the trace metal risk of contamination, and for example metallic impurity iron, nickel, zinc and al deposition are to silicon chip surface, and Fig. 3 is an example.Therefore, make metallic surface impurity be difficult to remove.Because existing, metallic impurity such as iron cause wafer surface slightly poor simultaneously.Just because of above-mentioned factors, need to adopt HPM mixing cleaning solution to carry out subsequent technique and clean.Effectively clean, remove metallic impurity in order to improve APM, can add complexometric reagent or surface-active agents.But at present this to be useful for complexometric reagent or surface-active agents that the silicon semiconductor unicircuit makes available few especially.
Silicon nitride is in the widespread use of many microelectronics and become one of most important material.For example, electric isolation in the logic CMOS ic manufacturing process, Technology generation no matter from several microns to 0.25 micron, electric isolation adopts local field oxidation (LOCOS) or its improved technology technology, still at present advanced more from 0.18 micron to 0.09 micron Technology generation, electric isolation adopts shallow-trench isolation (STI) Technology, but they all use silicon nitride film as mask material.Therefore, no matter in the LOCOS Technology, still fill out after operations such as groove, CMP finish, must carry out silicon nitride film to peel off the removal step, just can carry out postchannel process at STI dry etching, HDP.
In the integrated circuit fabrication process process, use different wet methods to peel off silicon nitride film.So far wet method is peeled off silicon nitride film technology under the 85% phosphoric acid heating condition of still employing routine.This is because it has the advantage of high ratio.Generally, silicon nitride film is peeled off and is adopted the phosphoric acid that heats as etching reagent, and it has the corrosion selectivity the highest to silicon-dioxide.Yet also there is shortcoming in this technology, and promptly surface particles increases and residual phosphorus contamination problem.
Therefore, the present invention proposes solution to the problems described above, after the heated phosphoric wet method is peeled off the silicon nitride film step, use new APM cleaning solution prescription to realize removing the purpose of surface particles and residual phosphorus contamination.
Summary of the invention
The objective of the invention is to propose a kind of new cleaning solution, peel off existing problems to solve the silicon nitride wet method, and propose the using method of this cleaning solution.
The cleaning solution that the present invention proposes, form by ammoniacal liquor, hydrogen peroxide, ultrapure water (UPW), tetramethyl-oxyammonia (TMAH) and complexometric reagent (CA) CDTA, the volume ratio of ammoniacal liquor, hydrogen peroxide and ultrapure water is 1 in the solution: (2-4): (20-40), TMAH in the above-mentioned mixing solutions (2.38%) add-on is (0.2-0.04) % of gross weight, and the content of CDTA is 5-100ppm.
In the above-mentioned mixing solutions, ultrapure water (UPW) content can be (75-94) %.
When cleaning solution uses, use million sound vibration technology to clean, can improve and remove the particle performance.Million sound vibration frequency are 0.8-1.5MHz, and million sound vibrations can energy density be 100-400W/cm
2Cleaning temperature when mixing solutions cleans is 30-75 ℃, and scavenging period is decided according to the different process step, and typical case's time is 5 to 20 minutes.
The principle of the invention is, on very rare standard A PM mixing solutions basis, adds tetramethyl-oxyammonia TMAH and complexometric reagent CDTA, and the CDTA molecular structure as shown in Figure 3.Adding the TMAH effect is because molecular volume is big more a lot of than ammoniacal liquor, has avoided traditional APM to cause the thick poor problem in surface like this, as shown in Figure 5.Add complexometric reagent CDTA effect and be remedy ammoniacal liquor can't some metal ion shortcoming of complexing.
The cleaning solution prescription that the present invention proposes can solve the silicon nitride film wet method and peel off existing problems.
Following advantage is specifically arranged: high particle removal efficiency; Phosphorus impurities stains very little; Low metallic impurity remnants; Good micro-content organism is removed efficient; The surface microroughness is very little; Reduce chemical reagent/DI water consumption; Reduce waste treatment; Reduce production costs.After purging method cleaning of the present invention, can satisfy the super large-scale integration Technology fully to requirements such as wafer metal, particle contaminants.
Description of drawings
Fig. 1 is that different chemical composition ratio SC1 removes the particulate efficiency synoptic diagram.Illustrate: DIW represents ultrapure water, and ME represents to use million sound vibration energy, and A, B, C represent three kinds of different chemical composition ratio SC1 mixing solutionss.
Fig. 2 is SC1 existing problems under 70 ℃ of conditions: ammonia (NH
3H
2O) volatilization and hydrogen peroxide (H
2O
2) decomposing schematic representation.As seen from the figure, in ultrapure chemical reagent, ammonia volatilization is more faster than decomposing hydrogen dioxide solution.
Fig. 3 is that metallic iron stains problem: silicon chip soaked 10 minutes in 70 degree SC1.Concentration is the log-linear relation in metallic iron surface concn and the solution as seen from the figure!
Fig. 4 is CDTA; 1,2-diethyl ammonium hexanaphthene tetraacethyl schematic arrangement.
Fig. 5 is that macromole TMAH reduces a kind of mechanism synoptic diagram of surperficial microroughness.
Embodiment
Concrete implementation step of the present invention is as follows.
The preparation of the first step cleaning solution:
1, cleaning solution preparation is measured ultrapure water (volume ratio is 70%) with graduated cylinder, pours in the clean Sheng solution rinse bath.
2, accurately measure 50ppm CDTA with graduated cylinder, slowly pour in the above-mentioned Sheng high purity water rinse bath.
3, accurately measure TMAH with graduated cylinder, content is 0.1%, slowly pours in above-mentioned Sheng 1,2 rinse baths.
4, measure a certain amount of 30% hydrogen peroxide (volume ratio is 10%) with graduated cylinder, slowly pour in above-mentioned Sheng 1,2,3 rinse baths.
5, measure a certain amount of ammoniacal liquor (29%NH with graduated cylinder
3H
2O), content is 3%, slowly pours in above-mentioned Sheng 1,2,3,4 rinse baths.
6, finish in above-mentioned 1 to 5 step after, allow various compositions mix at least and wait for half an hour, just can be used for technology and clean.
7, cleaning solution is heated to the temperature of processing requirement, and representative temperature is 35 ℃.
8, scavenging period is decided as the case may be, and typical case's time is 15 minutes.
Second step cleaned:
At first carry out hot phosphoric acid wet method and peel off silicon nitride film, use cleaning solution prescription of the present invention to clean then, open million sound vibrations simultaneously, its frequency is 0.1-1.5MHz, for example is set at 1MHz, and energy density is 100-400W/cm
2, for example be 200W/cm
2
The cleaning performance assessment
Can assess cleaning performance of the present invention by the following several respects characteristic of monitoring.
1, with total X-ray fluorescence spectra commercial measurement trace metal surface concns such as (TXRF)
2, adopt light scattering technique assessment particle removal efficiency
3, adopt the organic contamination of " flight time "-second ion mass spectroscopy (TOF-SIMS) commercial measurement.
The result shows that cleaning performance is very good.
Claims (3)
1, the cleaning solution of using in a kind of integrated circuit technology manufacturing, it is characterized in that: this cleaning solution is made up of ammoniacal liquor, hydrogen peroxide, ultrapure water, tetramethyl-oxyammonia and complexometric reagent CDTA, wherein the volume ratio of ammoniacal liquor, hydrogen peroxide and ultrapure water is 1: (2-4): (20-40), tetramethyl-oxyammonia (2.38%) content is (0.2-0.04) % of gross weight, and CDTA content is 5-100ppm.
2, a kind of using method of cleaning solution as claimed in claim 1 is characterized in that: use million sound vibration technology to clean, million sound vibration frequency are 0.8-1.5MHz, and million sound vibrations can energy density be 100-400W/cm
2
3, the using method of cleaning solution according to claim 2 is characterized in that: the mixing solutions cleaning temperature is 30-75 ℃, and scavenging period is 5 to 20 minutes.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2003101094597A CN1546627A (en) | 2003-12-16 | 2003-12-16 | Novel cleaning solution for the stripping of silicon nitride film in wet method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2003101094597A CN1546627A (en) | 2003-12-16 | 2003-12-16 | Novel cleaning solution for the stripping of silicon nitride film in wet method |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101452845B (en) * | 2007-11-30 | 2010-05-26 | 上海华虹Nec电子有限公司 | Wet method corrosion process for silicon nitride film |
| CN101192507B (en) * | 2006-11-29 | 2011-07-20 | 上海华虹Nec电子有限公司 | Phosphoric acid solution exchanging method in semiconductor integrated circuit production |
| CN101770931B (en) * | 2008-12-30 | 2011-10-05 | 中芯国际集成电路制造(上海)有限公司 | Method for removing organic particle impurities on wafer surface |
| WO2011154875A1 (en) * | 2010-06-09 | 2011-12-15 | Basf Se | Aqueous alkaline etching and cleaning composition and method for treating the surface of silicon substrates |
| US9748111B2 (en) | 2016-02-01 | 2017-08-29 | United Microelectronics Corp. | Method of fabricating semiconductor structure using planarization process and cleaning process |
| US10332741B2 (en) | 2017-05-08 | 2019-06-25 | United Microelectronics Corp. | Method for post chemical mechanical polishing clean |
-
2003
- 2003-12-16 CN CNA2003101094597A patent/CN1546627A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101192507B (en) * | 2006-11-29 | 2011-07-20 | 上海华虹Nec电子有限公司 | Phosphoric acid solution exchanging method in semiconductor integrated circuit production |
| CN101452845B (en) * | 2007-11-30 | 2010-05-26 | 上海华虹Nec电子有限公司 | Wet method corrosion process for silicon nitride film |
| CN101770931B (en) * | 2008-12-30 | 2011-10-05 | 中芯国际集成电路制造(上海)有限公司 | Method for removing organic particle impurities on wafer surface |
| WO2011154875A1 (en) * | 2010-06-09 | 2011-12-15 | Basf Se | Aqueous alkaline etching and cleaning composition and method for treating the surface of silicon substrates |
| CN103038311A (en) * | 2010-06-09 | 2013-04-10 | 巴斯夫欧洲公司 | Aqueous alkaline etching and cleaning composition and method for treating the surface of silicon substrates |
| US9076920B2 (en) | 2010-06-09 | 2015-07-07 | Basf Se | Aqueous alkaline etching and cleaning composition and method for treating the surface of silicon substrates |
| CN103038311B (en) * | 2010-06-09 | 2015-10-07 | 巴斯夫欧洲公司 | The method on aqueous alkaline etching and cleaning compositions and process silicon substrate surface |
| US9748111B2 (en) | 2016-02-01 | 2017-08-29 | United Microelectronics Corp. | Method of fabricating semiconductor structure using planarization process and cleaning process |
| US10332741B2 (en) | 2017-05-08 | 2019-06-25 | United Microelectronics Corp. | Method for post chemical mechanical polishing clean |
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