WO2009146606A1

WO2009146606A1 - Cleaning solution for removing residues from plasma etching

Info

Publication number: WO2009146606A1
Application number: PCT/CN2009/000623
Authority: WO
Inventors: 刘兵; 彭洪修; 于昊
Original assignee: 安集微电子科技(上海)有限公司
Priority date: 2008-06-06
Filing date: 2009-06-03
Publication date: 2009-12-10
Also published as: CN102047184A; CN101597548A; CN102047184B

Abstract

Cleaning solution for removing plasma etching residues contains solvent, water, fluoride, chelant, tertiary hydroxylamine and primary hydroxylamine. The cleaning solution has strong cleaning ability and can effectively remove the plasma etching residues on metal and semiconductor. The cleaning solution is useable in wide temperature range and has larger operating window. The cleaning solution has low rate of corrosion on metallic aluminum and non-metallic TEOS, and effectively reduces corrosion on Cu.

Description

Plasma etching residue cleaning liquid

The invention relates to a cleaning liquid in a semiconductor manufacturing process, and in particular to a plasma etching residue cleaning liquid. technical background

In the fabrication of semiconductor components, the application, exposure and imaging of the photoresist layer is a necessary process step for the pattern fabrication of the components. The residue of the photoresist layer material needs to be completely removed before the next process step (i.e., after coating, imaging, ion implantation, and etching of the photoresist layer). Ion bombardment in the doping step hardens the photoresist layer polymer, thus making the photoresist layer less soluble and more difficult to remove. Up to now, in the semiconductor manufacturing industry, this layer of photoresist film has been removed using a two-step process (dry ashing and wet etching). The first step utilizes dry ashing to remove most of the photoresist layer (PR); the second step utilizes the corrosion inhibitor composition wet etch/clean process to remove and clean the remaining photoresist layer, typically in the form of a cleaning solution. / rinse / deionized water rinse. Only the residual polymer photoresist layer and inorganic matter can be removed in this process, and the damage to the metal layer such as the aluminum layer cannot be attacked.

Typical cleaning solutions in the prior art are as follows: amine cleaning solution, semi-aqueous amine based (non-hydroxylamine) cleaning solution and fluorine cleaning solution. The first two types of cleaning fluids need to be cleaned at high temperatures, generally between 60 C and 80 ° C, and there is a problem of high corrosion rate to metals; while existing fluorine-based cleaning solutions can be used at lower temperatures (room temperature). Cleaning is carried out at 50 ° C), but there are still various disadvantages, such as the inability to simultaneously control the corrosion of metal and non-metal substrates, and the change in the size of the channel characteristics after cleaning, thereby changing the semiconductor structure; In terms of its large etching rate, the cleaning operation window is relatively small. The cleaning liquid composition disclosed in the patent US 6,828,289 comprises: Flushing, organic polar solvent, fluoride and water, and the pH is between 3 and 7, wherein the acidic buffer consists of an organic carboxylic acid or a polybasic acid and a corresponding ammonium salt, and the composition ratio is 10:1 to 1 : 10 between. A fluorine-containing cleaning liquid is disclosed in the patent US Pat. No. 5,698, 503, but the use of ethylene glycol in a large amount, the viscosity and surface tension of the cleaning liquid are large, thereby affecting the cleaning effect. A cleaning composition for a fluorine-containing substance comprising a fluorine-containing substance, an inorganic or organic acid, a quaternary ammonium salt and an organic polar solvent, having a pH of from 7 to 11, is disclosed in the patent US Pat. No. 5,972,862, which is The problem.

Thus, although some cleaning fluid compositions have been disclosed, there is a need and a greater need to prepare a more suitable cleaning composition or system to accommodate new cleaning requirements, such as a more environmentally friendly, low defect level, low etch rate. And a larger operating window. Summary of invention

The technical problem to be solved by the present invention is that in order to overcome the cleaning process in the semiconductor manufacturing process, the conventional amine cleaning liquid and the semi-aqueous amine based cleaning liquid need to be cleaned at a high temperature, and the corrosion rate to the metal is large, and the existing one contains After cleaning, the fluorine cleaning solution is easy to cause changes in the channel feature size and the cleaning operation window is small, and provides a safe, healthy and effective plasma etching residue cleaning liquid.

The present invention discloses a plasma etch residue cleaning solution comprising a solvent, water, a fluoride and a chelating agent, which further contains a hydroxyl tertiary amine and a hydroxy primary amine.

Wherein, the weight percentage of the hydroxyl tertiary amine is preferably from 0.1% to 20% _; the weight percentage of the primary hydroxylamine is preferably from 0.01% to 5%, more preferably from 0.1% to 1%; The weight percentage of the solvent is preferably from 30% to 75%; the weight percentage of the water is preferably from 15% to 65%; and the weight percentage of the fluoride is preferably from 0.1% to 20%. %; the weight of the chelating agent The percentage by weight is preferably from 0.1% to 20%, more preferably from 1% to 10%.

In the present invention, the hydroxyl tertiary amine is preferably one or more of N, N-dimethylethanolamine, N, N-methylethylethanolamine, N-methyldiethanolamine and triethanolamine. Triethanolamine is preferred; the hydroxyl primary amine is preferably one or more of monoethanolamine, propanolamine, butanolamine and diglycolamine, preferably monoethanolamine.

In the present invention, the solvent may be a solvent commonly used in the plasma etching residue cleaning liquid in the field, preferably one of sulfoxide, sulfone, imidazolidinone, pyrrolidone, imidazolidinone, amide and ether. Kind or more.

Wherein, the sulfoxide is preferably one or more of dimethyl sulfoxide, diethyl sulfoxide and methyl sulfoxide; and the sulfone is preferably methyl sulfone, ethyl sulfone and sulfolane. One or more; the imidazolidinone is preferably one of 2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, and 1,3-diethyl-2-imidazolidinone Or one or more; the pyrrolidone is preferably one or more of N-methylpyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone and N-hydroxyethylpyrrolidone; The imidazolinone is preferably 1,3-dimethyl-2-imidazolidinone; the amide is preferably dimethylformamide and/or dimethylacetamide; the ether is preferably ethylene glycol monoalkane One or more of a group ether, a diethylene glycol monoalkyl ether, a propylene glycol monoalkyl ether, a dipropylene glycol monoalkyl ether, and a tripropylene glycol monoalkyl ether.

Wherein, the ethylene glycol single-chamber ether is preferably one or more of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether; The ether is preferably one of diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether; the propylene glycol monodecyl ether is preferably propylene glycol monomethyl ether or propylene glycol single One or more of diethyl ether and propylene glycol monobutyl ether; the dipropylene glycol monodecyl ether is preferably one or more of dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether and dipropylene glycol monobutyl ether; The tripropylene glycol monoalkyl ether is preferably tripropylene glycol monomethyl ether. In the present invention, the fluoride may be a fluoride commonly used in the fluorine-containing cleaning liquid of the art, and is preferably a salt of hydrogen fluoride (HF), ammonium hydrogen fluoride (NH ₄ HF ₂ ), hydrogen fluoride and a base. Wherein, the base is preferably one or more of ammonia water, quaternary ammonium hydroxide and alcohol amine; the salt formed by the hydrogen fluoride and the base is preferably ammonium fluoride (NH ₄ F) or tetramethyl. One or more of ammonium fluoride (N (CH ₃ ) ₄ F) and trishydroxyethyl ammonium fluoride (N (CH ₂ OH) ₃ HF).

In the present invention, the chelating agent is a commonly used chelating agent in the plasma etching residue cleaning liquid in the field, and generally refers to a compound having a function of chelating a metal ion such as oxalic acid and citric acid. Preferably, the chelating agent of the present invention is selected from polyfunctional organic compounds containing a nitrogen atom, such as polyamino organic amines and/or amino acids.

Wherein the polyaminoorganic amine is preferably one or more of diethylenetriamine, pentamethyldiethylenetriamine and polyethenepolyamine, more preferably pentamethyldiethylenetriamine; Preference is given to one or more of 2-aminoacetic acid, 2-aminobenzoic acid, iminodiacetic acid, aminotriacetic acid and ethylenediaminetetraacetic acid, more preferably iminodiacetic acid. The chelating agent is most preferably a complex chelating agent of a polyamino organic amine and an amino acid, such as a complex chelating agent of iminodiacetic acid and pentamethyldiethylenetriamine, ammonia triacetic acid and pentamethyldiethylene triamine. A compounding chelating agent, or a complex chelating agent of iminodiacetic acid and diethylenetriamine.

The cleaning solution of the present invention may also contain other conventional additives in the art, such as metal aluminum copper corrosion inhibitors (e.g., benzotriazole).

The reagents and starting materials used in the present invention are commercially available.

The plasma etching residue cleaning liquid of the present invention can be obtained by simply and uniformly mixing the above components.

The plasma etching residue cleaning liquid of the invention is suitable for a wide range of use temperatures, generally in the room Temperatures up to 55 ° C, and suitable for a variety of cleaning methods, such as batch immersion (w _e t Batoh), batch rotary spray (Batch-spray) and single-piece rotary cleaning.

The positive effects of the present invention are:

(1) The cleaning solution of the present invention can effectively clean plasma etching residues generated in metal and semiconductor manufacturing processes without eroding SiO ₂ , ion-enhanced tetraethoxysilane silicon dioxide (PETEOS), silicon, low The dielectric material and some metal materials (such as Ti, Al, Cu) can make the metal wafer smooth when the metal wafer is cleaned.

(2) The cleaning liquid of the present invention can function in a relatively large temperature range, generally in the range of room temperature to 55 ° C, and at the same time, the cleaning liquid of the present invention maintains a small etching rate of metal and dielectric substances. .

(3) The cleaning liquid of the present invention effectively reduces the corrosion of copper while maintaining a low metal aluminum and non-metal TEOS corrosion rate.

(4) The cleaning liquid of the present invention has a strong cleaning ability and can simultaneously clean metal wire (Via)/metal pad (Pad) wafers.

(5) The cleaning liquid of the present invention has a large operation window and can be applied to a batch-spray/batch-spray/single wafer tool processor. DRAWINGS

Figure 1 shows an SEM image of an unwashed metal wafer cleaning.

Figure 2 is a SEM image of a metal wafer after cleaning in a comparative example.

3 is an SEM picture of the metal wafer cleaning of Example 33. Summary of the invention

The invention is further illustrated by the following examples, but the invention is not limited thereto. Example 1~29

Table 1 shows Examples 1 to 29, and each of the components in each of the examples was simply mixed to obtain a plasma etching residue cleaning liquid.

Table 1 Plasma etching residue cleaning solution Example 1~29

1,3-two

Pentamethyl

Triethanol single B

45 ammonium fluoride 1 30 diethylene 15 8.5 0.5

-2-imamine amine

Triamine

Oxazolidinone

N-methyl pentamethyl

Tetramethyltriethanol monoethylpyrrolidine 58 2 25 diethylene 10 4.8 0.2 ammonium fluoride amine alcohol amine ketone triamine

N-ethyl pentamethyl

Triethanol monoethylpyrrolidine 55. 5 ammonium fluoride 1 30 diethylene 2 10 1.5 amine alcohol amine ketone triamine

N-cyclohexane pentamethyl

Monoethylpyrrole 59 ammonium fluoride 0. 5 29. 4 diethylene 5 6 0.1 amine alcohol amine alkanone triamine

N-hydroxyethyltrihydroxyethylpentamethyl

Triethanol monoethylpyrrole 35 fluorinated 5 40 diethylene 4.9 15 0.1 amine alcohol amine fluorenone ammonium triamine

1,3- two tris

Pentamethyl

Methyl fluorinated triethanol single B

30 10 50 diethylene 6 3 1 -2-immonium amine amine amine

Triamine

Oxazolinone

Pentamethyl

Triethanol single B

44 Ammonium fluoride 1 40 Diethylene 12 2.5 0.5 Formamide Amine Alcoholamine

Triamine

Pentamethyl

Triethanol single B

59 Ammonium fluoride 1 32. 5 Diethylene 0.25 7 0.25 Acetamide Amine Alcoholamine

Triamine

Pentamethyl

Ethylene glycol triethanol single

59. 5 Ammonium fluoride 0. 5 35 Diethylene 3 1 1 Monomethyl ether Amine

Triamine

Pentamethyl

Ethylene glycol triethanol single

64. 5 Ammonium fluoride 0. 5 30 Diethylene 3 1 1 Monoethyl ether Amine

Triamine

Pentamethyl

Triethanol single B

64. 5 ammonium fluoride 0. 5 32 diethylene 1 1 1 monobutyl ether amine alcohol amine

Triamine

Diethylenedipentamethyl

Triethanol monoethanol monomethyl 49. 5 ammonium fluoride 0. 5 40 diethylene 8 1.5 0.5 amine alcohol amine ether triamine Diethylenedipentamethyl

Single B

21 Alcohol monoethyl 43 Ammonium fluoride 1 21 Diethylene 14.9 20 0.1 Amine Alcoholamine Ether Triamine

Diethylenedipentamethyl

Single B

22 Alcohol monobutyl 53 Ammonium fluoride 1 45 Diethylene 0.1 0.8 0.1 Amine Alcoholamine Ether Triamine

Trishydroxymethylpentamethyl

Propylene glycol

23 35-based fluorination 9 40 diethylene 6 9.5 0.5 monomethyl ether amine alcohol amine

Ammonium triamine

Trishydroxymethylpentamethyl

Propylene glycol, triethanol, single

24 35-based fluorination 20 35 diethylene 5 4 1 monoethyl ether amine alcohol amine

Ammonium triamine

Trishydroxymethylpentamethyl

Propylene glycol, triethanol, single

25 35-based fluorination 10 45 diethylene 5 4 1 monobutyl ether amine alcohol amine

Ammonium triamine

2

Dipropylene diethylene glycol diacetate

Triethanol single B

26 Alcohol monomethyl 40-fluorinated 3 45 pentamethyl 4.9 0.1 amine alcohol amine ether ammonium diethylene 5

Triamine

Dipropylene

Ammonia triethyl

Alcohol single B 20 5

Acid

Ether single B

27 Ammonium fluoride 1 42. 5 1.3 0.2 Pentamethylamine Alcoholamine

25 diethylene 5

Sulfoxide

Triamine

Dipropylene dihydroxy glycol

Imino triethanol single B

28 Alcohol monobutyl 60-fluorinated 3 35 0.1 1.8 0.1 Diacetic acid Amine Alcohol amine Ether ammonium

Imino

Tripropylene dihydroxy hydroxy 5

Diacetic acid triethanol single

29 Alcohol monomethyl 44 fluorinated 2 40 5.8 0.2 Diethylene amine Alcohol amine Ether ammonium 3

Triamine

Example 30

N-methylpyrrolidone 60 wt%; deionized water 28 wt%; ammonium fluoride 1.5 wt%; benzotriazole (BTA) 0.3 wt% _; iminodiacetic acid lwt%; diethylene triamine 3 wt%; triethanolamine 5.2 wt %; Monoethanolamine 1 wt%.

Example 31

N-methylpyrrolidone 60 wt%; deionized water 28 wt%; ammonium fluoride 1.5 wt%; citric acid 0.3 wt% _; iminodiacetic acid 3 wt%; diethylene triamine 3 wt%; triethanolamine 3.2 wt%; Ethanolamine 1 wt%.

Example 32

N-methylpyrrolidone 60 wt%; deionized water 28 wt%; ammonium fluoride 1.5 wt%; oxalic acid 0.05 wt%; iminodiacetic acid 3 wt% _; diethylene triamine 3 wt%; triethanolamine 3.2 wt%; monoethanolamine 1.25 wt% %.

Effect embodiment

In order to further embody the effects of the present invention, the corrosion rates of the metal aluminum, copper and non-metal TEOS were tested in Examples 33 to 35 and the comparative examples, and the metal wafer cleaning effects of the examples 33 and the comparative examples were as follows. 2 and Figure 3.

Test method for metal corrosion rate of solution:

1) Using a Napson four-point prober to test the initial resistance value (Rsl) of a 4*4 cm aluminum blank silicon wafer;

2) immersing the 4*4 cm aluminum blank silicon wafer in a solution that has been previously thermostated to 35 ° C for 30 minutes;

3) Remove the 4*4cm aluminum blank silicon wafer, wash it with deionized water, dry it with high purity nitrogen, and test the resistance value (Rs2) of 4*4cm aluminum blank silicon wafer with Napson four-point probe instrument;

4) Repeat the second and third steps and test again, the resistance value is recorded as Rs3;

5) Enter the resistance value and soak time into the appropriate program to calculate the corrosion rate. Non-metallic corrosion rate test method for solution -

1) Testing the thickness (T1) of the 4*4 cm PETEOS wafer using a Nanospec 6100 thickness gauge; 2) immersing the 4*4 cm PETEOS silicon wafer in a solution that has been previously thermostated to 35 ° C for 30 minutes;

3) Remove the 4*4cm PETEOS silicon wafer, wash it with deionized water, dry it with high purity nitrogen, and test the thickness of the 4*4cm PETEOS wafer (T2) with a Nanospec6100 thickness gauge;

4) Repeat the second and third steps and test the thickness again as T3;

5) Enter the above thickness value and soaking time into a suitable program to calculate the corrosion rate.

Comparison of Examples 33-35 and Comparative Example Formulations

in conclusion:

It can be seen from Table 2 that the combination of the primary alcohol amine and the tertiary alcohol amine effectively reduces the corrosion of copper while maintaining a low metal aluminum and non-metal TEOS corrosion rate. The results of the metal wafer cleaning of Comparative Example and Example 33 are shown in Figures 2 and 3.

It can be seen from Figure 1 that there are more photoresist residues on the metal lines of the uncleaned metal wafer. Figure 2 shows that although the comparative example can also clean the photoresist residue on the metal wafer, the metal fine line surface ratio Thicker, there are some pits. Figure 3 shows that the cleaning liquid of the present invention can not only clean the photoresist residue on the metal wafer, but also the surface of the fine metal wire is relatively smooth. Thereby, it is advantageous to improve the performance of the semiconductor device.

In summary, the cleaning solution of the present invention effectively reduces the corrosion of copper while maintaining a low metal aluminum and non-metal TEOS corrosion rate; and it can not only clean the photoresist residue on the metal wafer, but also The thin surface of the metal thin wire is smooth, which is beneficial to improve the performance of the semiconductor device.

Claims

Rights request

A plasma etching residue cleaning solution comprising a solvent, water, a fluoride and a chelating agent, characterized in that it further comprises a hydroxyl tertiary amine and a hydroxy primary amine.

The plasma etching residue cleaning solution according to claim 1, wherein the cleaning liquid is composed of the following components: a solvent, water, a fluoride, a chelating agent, a hydroxyl tertiary amine, and a hydroxy primary amine.

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the weight percentage of the tertiary hydroxylamine is from 0.1% to 20%.

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the hydroxy primary amine is 0.01% by weight to 5% by weight. .

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the solvent is 30% by weight to 75% by weight.

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the water has a weight percentage of 15% to 65%.

The plasma etching residue cleaning liquid according to claim 1 or 2, wherein the fluoride is present in a percentage by weight of 0.1% to 20%.

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the chelating agent has a weight percentage of 0.1% to 20%.

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the hydroxyl tertiary amine is N, N-dimethylethanolamine, N, N-methylethylethanolamine, N One or more of methyldiethanolamine and triethanolamine.

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the primary hydroxylamine is one of monoethanolamine, propanolamine, butanolamine and diglycolamine or A variety.

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the solvent is one of sulfoxide, sulfone, imidazolidinone, pyrrolidone, imidazolidinone, amide and ether. Or a variety.

The plasma etching residue cleaning solution according to claim 11, wherein the sulfoxide is one or more of dimethyl sulfoxide, diethyl sulfoxide and methyl sulfoxide. The sulfone is one or more of methyl sulfone, ethyl sulfone and sulfolane; the imidazolidinone is 2-imidazolium, 1,3-dimethyl-2-imidazolidinone and One or more of 1,3-diethyl-2-imidazolium; the pyrrolidone is N-methylpyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone and N-hydroxyethylpyrrole One or more of anthrone; the imidazolinone is 1,3-dimethyl-2-imidazolidinone; the amide is dimethylformamide and/or dimethylacetamide; The ether is one or more of ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, propylene glycol monodecyl ether, dipropylene glycol monoalkyl ether, and tripropylene glycol monodecyl ether.

The plasma etching residue cleaning solution according to claim 12, wherein the ethylene glycol monoalkyl ether is ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutylate. One or more of the ether; the diethylene glycol monoalkyl ether is one of diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether; The propylene glycol monoalkyl ether is one or more of propylene glycol monomethyl ether, propylene glycol monoethyl ether and propylene glycol monobutyl ether; the dipropylene glycol monoalkyl ether is dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether And one or more of dipropylene glycol monobutyl ether; the tripropylene glycol monoalkyl ether is tripropylene glycol monomethyl ether.

The plasma etching residue cleaning liquid according to claim 1 or 2, wherein the fluoride is one or more of hydrogen fluoride, ammonium hydrogen fluoride, and a salt of hydrogen fluoride and a base.

The plasma etching residue cleaning solution according to claim 14, wherein: The base is one or more of ammonia water, quaternary ammonium hydroxide and alcohol amine.

The plasma etching residue cleaning solution according to claim 14, wherein the hydrogen fluoride and the base form a salt of ammonium fluoride, tetramethylammonium fluoride and trishydroxyethylammonium fluoride. One or more.

The plasma etching residue cleaning solution according to claim 1 or 2, wherein the chelating agent is a polyamino organic amine and/or an amino acid.

The plasma etching residue cleaning solution according to claim 17, wherein: said polyamino organic amine is one of diethylenetriamine, pentamethyldiethylenetriamine and polyethenepolyamine. Or a plurality of; the amino acid is one or more of 2-aminoacetic acid, 2-aminobenzoic acid, iminodiacetic acid, aminotriacetic acid, and ethylenediaminetetraacetic acid.

The plasma etching residue cleaning solution according to claim 17, wherein: the chelating agent is a complex chelating agent of iminodiacetic acid and pentamethyldiethylenetriamine, ammonia triacetic acid and five a complex chelating agent for methyldiethylenetriamine, or a complex chelating agent for iminodiacetic acid and diethylenetriamine.