KR100679007B1 - Cleaning composition for semiconductor device - Google Patents

Abstract

The present invention relates to a composition for cleaning semiconductor substrates (including devices, silicon wafers, LCDs, photomasks, etc.) and other semiconductor devices. And other additives, such as chelating agents or surfactants, are mixed with the alkaline cleaner SC1 (standard clean 1; APM), which is used to clean particles, including photomasks. And calcium, iron, zinc, etc.).

Semiconductor Device, Particle Adsorption, Metal Impurity Contamination, SC1, Cleaner

Description

Cleaning composition for semiconductor device

1 illustrates the adsorption mechanism of the surfactant used in the present invention.

Figure 2 is a measurement result of the particle resorption prevention ability of the catechol in Experimental Example 1-1.

a) shows resorption test results for aluminum particles.

b) shows the results of the resorption experiment on silica particles.

c) shows the results of resorption experiments on PSL (polystyren latex) particles.

3 is a measurement result of the hydrogen peroxide decomposition prevention capacity of DTPMP in Experimental Example 1-2.

4 is a result of measuring the tungsten corrosion protection effect of the chelating agent in Experimental Example 1-3.

a) is a measure of the corrosion protection effect of increasing catechol concentrations.

b) measures the corrosion protection effect of increasing concentration of DTPMP.

5 is a measurement result of the metal ion resorption amount of the composition of Example 1.

6 is a measurement result of the metal ion cleaning power of the composition of Example 1.

7 is a particle cleaning power measurement results of the composition of Example 2.

8 is a result of measuring cleaning power of the composition of Example 2.

9 is a measurement result of the metal ion cleaning power of Examples 3 and 4.

10 shows particle cleaning power measurement results of Examples 3 and 4 compositions.

11 is a result of measuring the metal ion cleaning power of the composition of Example 5.

12 is a result of measuring particle cleaning power of a composition of Example 5.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for cleaning semiconductor devices including silicon wafers, silicon wafers, LCDs, photomasks, and the like for semiconductor devices. Chelating agents and surfactants or other additives are mixed with alkaline cleaner SC1 (standard clean 1; APM), which is used for particle cleaning of LCDs, photomasks, etc.). It relates to a cleaning composition for a semiconductor device capable of preventing contamination of aluminum, calcium, iron, zinc and the like).

As the degree of integration of semiconductor integrated circuits increases from megabit (Gbit) to gigabit dynamic random access memory (DRAM), the necessity of processing a fine pattern of a structure in which several kinds of semiconductor thin films are stacked in multiple layers is gradually increased. It is increasing. Accordingly, in order to reduce process defects generated during semiconductor device manufacturing, each substrate process is completed, and substrate cleaning processes (eg, oxidation process, diffusion process, photo process, etching process, etc.) are removed from the wafer surface before and after each process. Due to the necessity of the cleaning process to be carried out for the purpose of cleaning, the importance of the pollution control and the management cost are increasing exponentially.

A representative example of a cleaning process widely used for cleaning semiconductor substrates is megasonic in SC1, one of RCA cleaning methods based on ammonia water (NH ₄ OH) and hydrogen peroxide (H ₂ O ₂ ), developed by RCA in 1970. The washing | cleaning process which combined these is mentioned. The SC1 cleaning process uses a mixture of 65-95 ° C. in which ammonia, hydrogen peroxide and ultrapure water (H ₂ O) are mixed at a volume ratio of 1: 1: 5 or 1: 4: 20 as a cleaning liquid. Contaminants are removed from the surface of the substrate in such a manner that oxidation and fine etching of the silicon surface by ammonia are simultaneously performed. The value between pH 10 and 11 of the SC1 solution causes the silicon substrate and particles such as silica, alumina, and PSL to have the same zeta potential value. Particles are not resorbed to the wafer surface, and the megasonic irradiated together serves to move and remove the detached particles away from the wafer surface. However, when the cleaning process is applied to remove the contaminants on the wafer surface, high efficiency can be obtained in terms of particle removal. However, several problems occur during cleaning.

First, as the pattern of the device becomes finer, the size of particles to be managed also decreases, while the conventional SC1 has a problem in removal efficiency for fine particles of 0.10 microns or less. This is because particles smaller than 0.10 micron are easily decontaminated from silicon wafer surface by the oxidation and reduction of SC1 and the ultrasonic method with the frequency of 1KHz compared to the larger particles. to be.

Second, since hydrogen peroxide, an oxidant in the cleaning solution, can be accelerated by accumulation of 3d transition elements such as iron, nickel, and copper continuously flowing into the cleaning solution, the concentration of the cleaning solution is diluted due to the water generated during decomposition of hydrogen peroxide. And the lifetime of the cleaning liquid is reduced. In addition, a large amount of bubbles generated during the decomposition of hydrogen peroxide reduces the cleaning effect of the particles by megasonic. In addition, this requires a large amount of hydrogen peroxide and ammonia in the cleaning operation, which leads to an increase in the cost of the chemical solution.

Third, in the aqueous alkali solution, metals such as iron and aluminum are present in the form of ultrafine particles such as iron hydroxide and aluminum oxide, so that they are easily resorbed to the wafer surface, and formation of an oxide layer by hydrogen peroxide during the reaction in SC1 described above. Metal contamination is inevitably caused by the reason that metal contamination is contained in the oxide layer, which provides a reason for introducing an SC2 cleaning process.

Fourth, SC1 causes chemical erosion of metallization materials of devices such as aluminum and tungsten to provide a cause of device failure. This is particularly facilitated by the decomposition process of hydrogen peroxide.

In other words, the cleaning solution of SC1 (ammonia water / hydrogen peroxide / ultra pure water), which is an alkali cleaner used for particle cleaning, is vulnerable to particle cleaning of 0.10 μm or less. Since the cleaning process causes contamination of certain metal impurities (aluminum, calcium, iron, zinc, etc.), it is inevitable to use a secondary cleaning process by SC2, and hydrogen peroxide is applied to certain metal ions (particularly 3d transition elements) and organics. Due to its rapid decomposition, the cleaning power is also drastically reduced, and there is a problem of causing excessive erosion of aluminum and tungsten.

Therefore, it is urgent to develop a new semiconductor element cleaning solution that can solve the above problems.

Therefore, the present invention is a new concept of a detergent which is a combination of a polymer organic alcohol compound, a chelation substance, and a radical substance to solve the above-mentioned fundamental problems of the existing SC1. It is a cleaning agent of the concept that gives cleaning ability to metal ions.

An object of the present invention is to provide a semiconductor cleaning composition that can remove particles and metal impurities at a time by eliminating the hassle of performing SC2 cleaning after SC1 cleaning in the conventional semiconductor device cleaning process.

In addition, an object of the present invention is to provide a semiconductor cleaning composition that can remove particles and metal impurities all at once by adding a chelating agent and a surfactant to the composition of the existing SC1 cleaning solution.

In order to achieve the above object, the present inventors add a chelating agent and a surfactant or other additives to the SC1 cleaning solution, which is an alkaline cleaner used for particle cleaning of existing semiconductor devices (including devices, Si wafers, LCDs, and photomasks). A semiconductor device cleaning composition has been developed to remove metal impurities such as aluminum, calcium, iron, and zinc at once.

The present invention is a mixture of 29wt% ammonia, 31wt% hydrogen peroxide, ultrapure water in a volume ratio of 1: 1 to 4: 5-20 and DTPMP (Diethylenetriamine-N, N, N ', N ", N" -Pentakis (methylenephosphonic acid)) or CDTA (Trans-1,2-diaminocyclohexane tetraacetic acid) and catechol, 4-tert-butylcatechol or 2,3-naphthalenediol (2 , 3-naphthalenediol) relates to a semiconductor device cleaning composition containing 10 to 10000 mg / L of the chelating agent mixed with one selected from a molar ratio of 2: 0.1-2.

The chelating agent is mixed with DTPMP and catechol in a molar ratio of 2: 0.1-2, and added at a concentration of 10-10000 mg / L based on the final cleaning solution. The addition of less than 10 mg / L is insignificant, if more than 10000 mg / L is not economical.

In addition, the present invention is characterized by adding one or two or more of the above-described cleaning compositions in the group consisting of nonionic surfactants, radical initiators and radical decomposers.

In addition, the present invention is characterized in that the nonionic surfactant, the radical initiator and the radical decomposing agent are contained in 1 ~ 1000mg / L, 10 ~ 100000mg / L, 10 ~ 100000mg / L, respectively, with respect to the final cleaning composition do.

It is added at a concentration of 1 to 1000 mg / L relative to the final cleaning liquid composition of the nonionic surfactant. Adding an amount less than 1 mg / L is ineffective and adding an amount exceeding 1000 mg / L is not economical.

The radical initiator and the radical decomposer add 10 mg / L to 100000 mg / L, respectively, to the final washing liquid composition. Adding an amount less than 10 mg / L is ineffective and adding an amount exceeding 100000 mg / L is not economical.

In addition, the present invention is characterized in that the nonionic surfactant is an aliphatic polyhydric alcohol.

In addition, the radical initiator is the radical initiator is 2,2-azobis (2-methylpropionitrile) (2,2-azobis (2-methylpropionitrile)) or 2,2-azobis hydrogen chloride (2, 2-azobis hydrochloride).

In addition, the present invention is characterized in that the radical decomposition agent is tert-butyl hydrogen peroxide (tert-butyl hydrogen peroxide).

The present invention is a metal that is a disadvantage of SC1 by adding a chelating agent in the form of a mixture of DTPMP or DTPPH (Diethylenetriamine-N, N, N ', N ", N" -Pentakis (methylene-phosphonic acid) and catechol). The problem of re-adsorption of impurities was solved The two chelation materials were found to have a better cleaning effect on metal ions and particles when used in combination than when used alone.

The improvement of the cleaning effect on metal ions is different from each other in the stability constant value of the DTPMP and the catechols with respect to the individual metal ions, and the difference in the chelation between the DTPMP and the catechols is mutually different. Because it complements.

Improving the cleaning effect on the particles is also achieved because catechol's ability to prevent resorption of particles and DTPMP can compensate for the problem of particle desorption of catechol. At this time, instead of the catechol, 4-tert-butyl catechol (4-tert butyl catechol) or 2,3-naphthalenediol may be used in the same amount.

As the nonionic surfactant, a polyhydric alcohol (aliphatic polyhydric alcohol) system is used, and in the present invention, a nonionic surfactant mainly uses Drynon-C (trade name, manufactured by NIKKA-SEICO), which is an aliphatic polyhydric. A polymer mixture of alcoholic (aliphatic polyhydric alcohol), glycol type solvent, and pure water, which penetrates between the silicon substrate and particles without coordinating to the surface of desorbed particulate matter like a common surfactant. The material completely encloses the particles, thus preventing particle desorption and resorption.

That is, the present invention is the addition of the DTPMP / catechol mixture For some ions (aluminum, copper), superior cleaning effects can be expected over SC2 (standard clean-2; HPM), which extends the life of cleaning compositions, prevents corrosion of metal wiring and particle cleaning, which is a unique feature of SC1. You can expect.

 The addition of nonionic surfactants, especially Drynon-C, is expected to clean particles by preventing particle desorption and resorption, and also suppresses damage such as pitting on the surface of the silicon wafer, similar to the addition of surfactants. You can do it.

In addition, the radical initiator or the radical decomposing agent can further improve the desorption capacity of the metal ions and the particles by the SC1 cleaner. Radical initiation or decomposition products in a stable state are decomposed into radical materials by the catalysis of metal ions, and in the process, desorption of metal ions and particles is promoted by oxidation and reduction reactions. Simultaneous use of radicals and chelating materials has the effect of delaying the decomposition of radicals, so the rapid decomposition of hydrogen peroxide by radicals is not observed and the lifetime of SC1 was not different from the existing SC1.

Hereinafter, the configuration of the present invention will be described in detail through examples. However, the scope of the present invention is not limited to the following examples.

Example 1

A mixture of ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 (volume ratio; aqueous solution having a concentration of 29% by weight ammonia water and 31% by weight hydrogen peroxide) mixture of DTPMP / catechol = 2/1 (molar ratio) based on the final composition 200 mg / L was added to prepare 70 L of a cleaning composition.

Example 2

Prepared in a mixture of ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 (volume ratio; aqueous solution having a concentration of 29% by weight ammonia and hydrogen peroxide: 31% by weight) and based on the final composition, DTPMP / catechol = 2/1 (molar ratio) ) 200 mg / L mixture and 50 mg / L of drynon-C (Aliphatic polyhydric alcohol, a polymer mixture of Glycol type solvent and Pure water; NIKKA-SEICO) were added to prepare 70 l of the cleaning composition.

Example 3

A mixture of ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 (volume ratio; aqueous solution having a concentration of 29% by weight ammonia water and 31% by weight hydrogen peroxide) mixture of DTPMP / catechol = 2/1 (molar ratio) based on the final composition 70 L of a cleaning composition was prepared by adding 200 mg / L and 50 mg / L of 2,2-azobis (2-methylpropionitrile) as a radical initiator.

Example 4

A mixture of ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 (volume ratio; aqueous solution having a concentration of 29% by weight ammonia water and 31% by weight hydrogen peroxide) mixture of DTPMP / catechol = 2/1 (molar ratio) based on the final composition 200 mg / L and 200 mg / L of tert-butylhydrogenperoxide were added as a radical decomposer to prepare 70 L of a cleaning composition.

Example 5

Ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 (volume ratio; using aqueous solution having a concentration of 29% by weight ammonia water and 31% by weight hydrogen peroxide) DTPMP / catechol = 2/1 (molar ratio) mixture 200 based on final composition MG / L, Drynon-C (A polymer mixture of aliphatic polyhydric alcohol, Glycol type solvent and Pure water; NIKKA-SEICO) 50mg / L, TBHP (tert-butylhydrogenperoxide) 200mg / L as a radical decomposer for cleaning 70 L of the composition was prepared.

Comparative Example 1

70 L of a mixed solution of aqueous ammonia / hydrogen peroxide / ultra pure water = 1/4/20 (volume ratio; aqueous ammonia: 29 wt%, hydrogen peroxide: 31 wt%) was prepared.

Comparative Example 2

Ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 (volume ratio; aqueous solution having a concentration of 29% by weight of ammonia and 31% by weight of hydrogen peroxide) was added to the mixed solution to prepare a composition in which DTPMP 200 mg / L was added based on the final composition.

Comparative Example 3

Aqueous ammonia / hydrogen peroxide / ultra pure water = 1/4/20 (volume ratio; aqueous solution having a concentration of 29% by weight of ammonia and 31% by weight of hydrogen peroxide) to the mixed solution was added 200 mg / L of catechol based on the final composition Was prepared.

Experimental Example 1: Confirmation of properties of the chelating agent

1-1. Catechol  Particle resorption prevention effect

A mixture of ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 volume ratio (aqueous ammonia: 29% by weight, hydrogen peroxide: 31% by weight) was used as a control, and the mixture was prepared in the same conditions as the control. 70 L of a composition containing 200 mg / L of call and 200 mg / L of CDTA, respectively, were prepared.

To the 70 liter quartz container filled with the control and each composition, add particles (silica / alumina / polystyrene latex = 1/1/1 mixed particles) having a size of 0.08 to 0.11 μm so that the number of particles per 1 ml volume is 30000. The 8-inch wafer was deposited and megasonic (955 KHz.360 Watt) was added in parallel, followed by rinsing with ultrapure water for 6 minutes in a separate 70 L quartz vessel, followed by spin drying.

The dried wafer was measured using only Tencor 6220 particles of 0.11㎛ size is shown in Figure 2.

1-2. Comparison of prevention of hydrogen peroxide decomposition by DTPMP

A mixture of ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 volume ratio (aqueous ammonia: 29% by weight, hydrogen peroxide: 31% by weight) was used as a control, and DTPMP, CDTA, Catechol was added 200 mg / L each to prepare 70 L of cleaning composition, respectively.

Fe ions were added to each composition at 10 μg / L based on the composition. The concentration of hydrogen peroxide in each composition was measured in 10 minutes at 65 ° C. and shown in FIG. 3.

1-3. Comparison of Etch Rate for Tungsten Metallization

In this experimental example, the etching rate of tungsten was measured according to the concentration change of the chelating agent in the cleaning composition.

Aqueous ammonia / hydrogen peroxide / ultra pure water = 1/4/20 volume ratio (using an aqueous solution having a concentration of 29% by weight of ammonia water and 31% by weight of hydrogen peroxide) in the mixture with catechol 0, 250, 500, 1000, 2000, 1 L of a composition containing 3000 mg / L was prepared.

And in the mixture of ammonia water / hydrogen peroxide / ultra pure water = 1/4/20 volume ratio (using an aqueous solution having a concentration of 29% by weight of ammonia and 31% by weight of hydrogen peroxide) in the mixture, catechol 0, 250, 500, 1000, 1500 based on the final composition. , 1 mg of a composition containing 2000 mg / L was prepared.

Tungsten metal rods were deposited for 10 minutes in a 1 liter container filled with the respective composition heated to 60 ° C. and tungsten was analyzed and described in FIGS. 4A and 4B.

Experimental Example 2: Measurement of resorption amount of metal ions of Example 1 composition

In this Experimental Example, the amount of resorption of metal ions was measured using the composition of Example 1 and Comparative Examples 1 to 3.

Each composition was artificially contaminated at a concentration of 1 ppb for each of the elements of Na, Al, Ca, Cr, Fe, Ni, Cu, and Zn, and a clean 8-inch silicon wafer was immersed and cleaned for 6 minutes with megasonic at 70 ° C. After rinsing for 6 minutes with ultrapure water in a separate 70 L quartz vessel and spin-dried.

The dried wafer was extracted with metal ions on the surface of the wafer using a mixture of hydrofluoric acid and hydrogen peroxide and analyzed by ICP-MS to determine the amount of metal ions adsorbed on the wafer. 5 shows the adsorption amount for each of the above elements graphically.

Experimental Example 3: Comparison of cleaning power of metal ions of Example 1 composition

The 8-inch silicon wafer, which was artificially contaminated to maintain a constant level, was deposited and cleaned for 6 minutes in a 70 L quartz container using the compositions of Examples 1 and Comparative Examples 1 to 3, followed by 6 minutes of ultrapure water in a separate 70 L quartz container. Rinse and spin dry.

The dried wafer was extracted with metal ions on the wafer surface using a mixture of hydrofluoric acid and hydrogen peroxide, and analyzed by ICP-MS. The results are shown in FIG. 6.

Experimental Example 4: Comparison of Particle Cleaning Strength of the Composition of Example 2

In this Experimental Example, the particle cleaning power was measured. Megasonic (955 kHz) was carried out at 70 ° C. using the composition of Comparative Examples 1 and 1 and 2 on a wafer subjected to CMP using an alkali slurry composed mainly of silica particles and organics. , 300Watt) was irradiated for 10 minutes, rinsed with ultrapure water for 6 minutes, spin-dried and only particles of 0.065 μm or more were measured using SP1, and are shown in FIG. 7.

Experimental Example 5: Comparison of cleaning power of the composition of Example 2

In this experiment, the 8-inch silicon wafer, which was artificially contaminated to maintain a certain level on the surface, was washed with HPM (hydrochloric acid peroxide mixture (SC2), FPM (HF / H ₂ O ₂ ) cleaning composition and The cleaning composition was irradiated with megasonic (955 kHz, 300 Watts) at 70 ° C. for 6 minutes, then rinsed with ultrapure water for 6 minutes and spin-dried.

The dried wafer was extracted with metal ions on the surface of the wafer using a mixture of hydrofluoric acid and hydrogen peroxide to measure the respective contents thereof, and the results are shown in FIG. 8.

Experimental Example 6: Comparison of metal ion cleaning power of the compositions of Examples 3 and 4

An 8-inch silicon wafer that was artificially contaminated to maintain a certain level on the surface of the silicon wafer was immersed for 6 minutes while irradiating megasonic (955 kHz, 300 Watts) to each of the 70 ° C. compositions of Examples 1, 3, and 4, followed by a separate 70L. Rinse with ultrapure water for 6 minutes in a quartz container and spin-dry.

The dried wafer was extracted with metal ions on the wafer surface using a mixture of hydrofluoric acid and hydrogen peroxide, and analyzed by ICP-MS, and the results are shown in FIG. 9.

Experimental Example 7: Comparison of Particle Cleaning Strength of Examples 3 and 4 Compositions

In order to compare the particle cleaning power, megasonic (955 kHz, 300 Watts) was irradiated to the 70 ° C. cleaning composition of Example 1 and Example 3. The wafer was subjected to CMP using an alkali slurry composed mainly of silica particles and organic materials. After washing for 10 minutes while rinsing with ultrapure water for 6 minutes and spin-dried. The dried wafer was measured only particles of 0.065 ㎛ size or more using SP1 and the results are shown in FIG.

Experimental Example 8: Comparison of metal ion cleaning power of Example 5 composition

In this experimental example, an 8-inch silicon wafer which was artificially contaminated to a certain level to measure the gold cleaning power of the composition of Example 5 was deposited for 6 minutes while irradiating the composition of Example 5 to the composition of Example 5 at megasonic (955 kHz, 300 Watt). After washing, the resultant was rinsed with ultrapure water for 6 minutes in a separate 70 L quartz container, followed by spin drying. The dried wafer was extracted with metal ions on the wafer surface using a mixture of hydrofluoric acid and hydrogen peroxide, and analyzed by ICP-MS, and the results are shown in FIG. 11.

Experimental Example 9: Comparison of Particle Cleaning Strength of the Composition of Example 5

In this experimental example, in order to measure the particle cleaning power, the wafers subjected to CMP using an alkali slurry containing silica particles and organic substances as main components were each prepared in megasonic (955 kHz, 300Watt) was irradiated for 10 minutes, rinsed with ultrapure water for 6 minutes, spin-dried and only particles of 0.065 μm or more were measured using SP1, and the results are shown in FIG. 12.

It was found that the number of particles remaining in the wafer cleaned in the composition of Example 5 was much smaller than that of the conventional SC1 composition.

The present invention may provide a composition for cleaning a semiconductor device in which a chelate mixture and a surfactant or a radical material are mixed to prevent particle resorption and the metal impurities are removed.

In addition, the cleaning composition of the present invention is economical because it can achieve the effect of removing particles, preventing re-adsorption of particles, and removing metal ions by one washing without a repeated washing process.

Claims (6)

delete delete DTPMP (Diethylenetriamine-N, N, N ', N ", N"-Pentakis (methylenephosphonic acid) in a mixed solution containing 29 wt% ammonia, 31 wt% hydrogen peroxide and ultrapure water in a volume ratio of 1: 1 to 4: 5 to 20 ) Or CDTA (Trans-1,2-diaminocyclohexane tetraacetic acid) and catechol, 4-tert-butylcatechol or 2,3-naphthalenediol (2,3 -naphthalenediol) in the final composition to which a chelating agent is added a mixture of one selected from molar ratio of 2: 0.1 ~ 2, the non-ionic surfactant in addition to the composition for cleaning semiconductor devices containing 10 to 10000 mg / L The nonionic surfactant and radical in the composition for cleaning a semiconductor device, characterized in that one or two or more are added from the group consisting of tert-butyl hydrogen peroxide as a radical initiator and a radical decomposing agent. Tert-butylhydrogen as initiator and radical decomposer Peroxide (tert-butyl hydrogen peroxide) the composition for washing a semiconductor device which is characterized in that each one to contain a 1000㎎ / L, 10 ~ 100000㎎ / L, 10 ~ 100000㎎ / L with respect to the composition for the final cleaning. The method of claim 3, wherein the nonionic surfactant is a semiconductor device cleaning composition, characterized in that the aliphatic polyhydric alcohol (aliphatic polyhydric alcohol) system. delete delete

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