TW201311882A - Fluorine-containing cleansing solution - Google Patents

Abstract

The present invention discloses a fluorine-containing cleansing solution having a low etching rate towards silicon oxynitride and useful for the semiconductor industry. The cleansing solution composition comprises: a) fluoride of 0.1% ~ 20%; b) polyol of 0.01% ~ 20%; c) water of 5% ~ 75%; d) solvent of 1% ~ 75%; e) other additives of 0 ~ 20%. The cleansing solution composition of the present invention can effectively cleanse the ionic etching residues in the semiconductor manufacturing process, and simultaneously has a lower etching rate towards the substrates such as low dielectric material (SiO2, PETEOS) and some metal substances (e. g. Ti, Al, Cu); particularly, lower etching rate towards silicon oxynitride can further enlarge the cleansing operation window of the fluorine-containing cleansing solution and further raise the service life of the fluorine-containing cleansing solution to lower the operation cost of the semiconductor plant, thereby having excellent application prospect in the microelectronic field of the semiconductor chip cleansing.

Description

Fluorine-containing cleaning solution

The present invention relates to a fluorine-containing cleaning liquid for semiconductor industry.

In the fabrication of semiconductor components, the application, exposure and imaging of the photoresist layer are necessary process steps for the pattern fabrication of the components. The residue of the photoresist layer material needs to be completely removed before the next process step (ie, after coating, imaging, ion implantation, and etching of the photoresist layer). Ion bombardment in the doping step hardens the photoresist 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 uses 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. In this process, only the residual polymer photoresist layer and the inorganic material can be removed, and the damage to the metal layer (such as the aluminum layer) and the non-metal layer (such as the hafnium oxynitride layer) cannot be attacked.

Typical cleaning solutions in the prior art are as follows: amine cleaning solutions (hydroxylamines), semi-aqueous amine based (non-hydroxylamine) cleaning solutions, and fluoride cleaning solutions. The first two types of cleaning liquids need to be cleaned at high temperature, generally between 60 ° C and 80 ° C, there is a problem of high corrosion rate of metal; while the existing fluoride cleaning liquid can be at a lower temperature (room Cleaning at temperatures up to 50 ° C), but there are still various shortcomings, such as the inability to simultaneously control the corrosion of metal and non-metal substrates, which can easily cause changes in the dimensions of the channel after cleaning, thereby changing the semiconductor structure; Due to its large etching rate, the cleaning operation window is relatively small. US 5,320,709 discloses a cleaning composition comprising: a polyol, ammonium fluoride for removing organometallic residues on a semiconductor substrate, residues of organic germanium and cerium oxide, but specifically indicating that the water content does not exceed 4%, and The removal ability of organic polymers is weak. The cleaning liquid composition disclosed in US 6,828,289 comprises: an acidic buffer, an organic polar solvent, a fluorine-containing substance and water, and a pH of between 3 and 7, wherein the acidic buffer is composed of an organic carboxylic acid or a polybasic acid. The ammonium salt composition has a composition ratio of between 10:1 and 1:10, and it is specifically indicated that it does not contain a polyol. For example, US 5,698,503 discloses a fluorine-containing cleaning liquid, but a large amount of a polyol is used in an amount of 55 to 85%; thus, the viscosity and surface tension of the cleaning liquid are large, thereby affecting the cleaning effect. A cleaning composition for a fluorine-containing substance, which comprises 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 US Pat. No. 5,972,862, which has various problems due to the fact that the cleaning effect is not very stable. .

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 Large operating window and long service life.

SUMMARY OF THE INVENTION The object of the present invention is to solve the problem of safe, healthy and efficient cleaning of intermediate ion etching residues in the semiconductor industry and to provide a safe and effective long-life cleaning composition.

The present invention is a cleaning fluid composition for intermediate ion etching residues in the semiconductor industry, including fluorides, polyols, water, solvents, and other conventional additives in the art. Other conventional additives known in the art include, but are not limited to, one or more of corrosion inhibitors and chelating agents.

The weight percentage of the cleaning liquid composition is:

a) fluoride 0.1% to 20%;

b) polyol 0.01% to 20%;

c) water 5% to 75%;

d) solvent 1% to 75%;

e) Other conventional additives in the art are 0-20%.

The fluoride according to the present invention is preferably hydrogen fluoride or a salt of hydrogen fluoride and a base. The base can be aqueous ammonia, quaternary ammonium hydroxides and alcohol amines. The fluoride is preferably hydrogen fluoride (HF), ammonium fluoride (NH ₄ F), ammonium hydrogen fluoride (NH ₄ HF ₂ ), tetramethylammonium fluoride (N(CH3) ₄ F) or trishydroxyethyl fluoride. One or more of ammonium (N(CH2OH) ₃ HF).

The polyol according to the present invention means a glycol, a triol, a tetrahydric alcohol, a pentaol, and a hexahydric alcohol. Preferred are ethylene glycol, 1,2-propanediol, glycerol, butanol, pentaerythritol, ribose, ribulose, glucose, glucose alcohol, hexahexaol, mannitol and sorbitol; more preferably Among the tetrahydric alcohols, pentahydric alcohols and hexahydric alcohols, tetramethylene alcohol, pentaerythritol, ribose, ribulose, glucose, glucose alcohol, hexitol, mannitol and sorbitol are preferred.

The invention may further comprise water.

In the present invention, the solvent may be selected from one or more of the group consisting of anthraquinone, anthracene, imidazolidinone, pyrrolidone, imidazolidinone, ether, and decylamine. Wherein, the hydrazine is preferably dimethyl hydrazine; the hydrazine is preferably cyclobutyl hydrazine; and the imidazolidinone is preferably 1,3- dimethyl-2-imidazole. The alkyl ketone; preferably, the pyrrolidone is N-methylpyrrolidone or hydroxyethylpyrrolidone; and the imidazolidinone is preferably 1,3-dimethyl-2-imidazolidinone (DMI); The ether is preferably propylene glycol monomethyl ether or dipropylene glycol monomethyl ether; the guanamine is preferably dimethylformamide or dimethylacetamide.

The cleaning solution of the present invention may also contain other conventional additives in the art, such as corrosion inhibitors and chelating agents. Its content generally does not exceed 20%. In the present invention, the corrosion inhibitor may be a corrosion inhibitor commonly used in the art, preferably from a benzotriazole, a carboxylic acid, a polycarboxylic acid, and a phosphonic acid. Corrosion inhibitors, etc. Such as benzotriazole, benzoic acid, polyacrylic acid, 1,3-(hydroxyethyl)-2,4,6-triphosphonic acid and the like. In the present invention, the chelating agent means an organic compound containing a plurality of functional groups. Preferred are glycolic acid, malonic acid, citric acid, iminodiacetic acid, ammonia triacetic acid, triethanolamine, ethylenediaminetetraacetic acid, catechol, gallic acid, salicylic acid, pentamethyldiethylenetriamine , sulfamic acid and sulfosalicylic acid, and the like.

The positive progress of the present invention is that the cleaning liquid composition of the present invention can function in a relatively large temperature range, generally in the range of room temperature to 55 ° C, and can be used in a wide range of fields, such as batch immersion. / Batch rotary / single-piece rotary. At the same time, the cleaning fluid composition has a lower etch rate of metal and dielectric materials.

The cleaning liquid composition of the present invention can also effectively clean medium ion etching residues in metal and semiconductor manufacturing processes without eroding SiO2, ion-enhanced tetraethoxydecane cerium oxide (PETEOS), cerium, cerium oxynitride and Some metal substances (such as Ti, Al, Cu). For the semiconductor manufacturing industry, the cleaning fluid compositions of the present invention can be used in batch soaking, batch rotation, and monolithic rotary processors.

We conducted performance tests using some of the examples in the above table to illustrate the effects of the present invention, and the results are shown in Table 2 below.

Test method for metal corrosion rate of solution:

1) Using the Napson four-point probe instrument to test the initial resistance value (Rs1) of the 4*4 cm aluminum blank sheet;

2) soaking the 4*4 cm aluminum blank sheet in a solution which has been previously thermostated to 40 ° C for 60 minutes;

3) Take out the 4*4cm aluminum blank slab, wash it with deionized water, dry it with high purity nitrogen, and test the resistance value (Rs2) of 4*4cm aluminum blank 利用 piece by Napson four-point probe instrument;

4) Enter the resistance value and soak time into the appropriate program to calculate the corrosion rate.

Test method for non-metallic corrosion rate of solution:

1) Test the thickness (T1) of 4*4cm yttria using a Nanospec6100 thickness gauge;

2) soaking the 4*4 cm PETEOS tablet in a solution that has been previously thermostated to 40 ° C for 60 minutes;

3) Take out the 4*4cm bismuth oxynitride sheet, wash it with deionized water, dry it with high purity nitrogen, and test the thickness (T2) of 4*4cm yttria sheet by Nanospec6100 thickness gauge;

4) Enter the above thickness value and soak time into the appropriate program to calculate the corrosion rate.

Wafer cleaning method:

1) placing the wafer to be cleaned into a solution that has been previously thermostated to 40 ° C;

2) Soak the wafer according to the principle of immersing the wire for 20 minutes, immersing the channel and the metal pad for 30 minutes;

3) After the immersion time is reached, the wafer is taken out, washed with deionized water, and dried after high-purity nitrogen gas; sent to SEM test.

It can be seen from Table 2 that the cleaning liquid composition of the present invention does not substantially erode metals (such as metal aluminum) and non-metals (such as bismuth oxynitride) used in semiconductor fabrication, and the etching rate is close to or smaller than that of the semiconductor. The industry usually requires 2 angstroms per minute. Cleaning the plasma etch residue with this solution revealed that the plasma etch residue was removed and there was no corrosion of metals and non-metals.

In summary, the cleaning liquid of the present invention has strong cleaning ability and can simultaneously clean metal/via/Pad wafers, and can simultaneously control the corrosion rate of metals and non-metals, especially oxynitride. The lower etch rate is beneficial to expand the cleaning operation window of the fluorine-containing cleaning liquid, prolong the service life of the cleaning liquid, and reduce the operating cost of the semiconductor factory. With a large operating window, it can be applied to both batch batch/batch-spray/single wafer tool.

Claims (14)

A fluorine-containing cleaning liquid comprising: fluoride, polyol, water, solvent; wherein: the polyol has a weight percentage of 0.01% to 20%, and the water has a weight percentage of 5% to 75%. The fluorine-containing cleaning liquid according to claim 1, wherein the fluoride has a weight percentage of 0.1% to 20%, and the solvent has a weight percentage of 1% to 75%. The fluorine-containing cleaning liquid according to claim 1, wherein the fluoride is hydrogen fluoride or a salt of hydrogen fluoride and hydrazine, and the hydrazine is ammonia water, quaternary ammonium hydroxide or alcohol amine. The fluorine-containing cleaning liquid according to claim 3, wherein the fluoride is hydrogen fluoride (HF), ammonium fluoride, ammonium hydrogen fluoride, tetramethylammonium fluoride, and/or trishydroxyethylammonium fluoride. The fluorine-containing cleaning liquid according to claim 1, wherein the polyol is a glycol, a triol, a tetrahydric alcohol, a pentahydric alcohol, and/or a hexahydric alcohol. The fluorine-containing cleaning liquid according to claim 5, wherein the polyol is ethylene glycol, 1,2-propylene glycol, glycerin, butyltetraol, pentaerythritol, ribose, ribulose, glucose, Glucitol, hexitol, mannitol and/or sorbitol. The fluorine-containing cleaning liquid according to claim 6, wherein the polyol is butanol, pentaerythritol, ribose, ribulose, glucose, glucose alcohol, hexahexaol, mannitol, and/or sorbitol. The fluorine-containing cleaning liquid according to claim 1, wherein the solvent is one or more selected from the group consisting of anthraquinone, anthracene, imidazolidinone, pyrrolidone, imidazolidinone, ether, and decylamine. The fluorine-containing cleaning liquid according to claim 1, wherein the hydrazine is dimethyl hydrazine; the hydrazine is cyclobutyl hydrazine; and the imidazolidinone is 1,3-dimethyl-2- An imidazolidinone; the pyrrolidone is N-methylpyrrolidone and/or hydroxyethylpyrrolidone; the imidazolidinone is 1,3-dimethyl-2-imidazolidinone; the ether is propylene glycol monomethyl ether and / or dipropylene glycol monomethyl ether; the guanamine is dimethylformamide and / or dimethyl acetamide. The fluorine-containing cleaning liquid according to claim 1, wherein the fluorine-containing cleaning liquid further contains other additives. The fluorine-containing cleaning liquid according to claim 10, wherein the other additives are contained in an amount of not more than 20% by weight. The fluorine-containing cleaning liquid according to claim 10, characterized in that the other additive is a corrosion inhibitor and/or a chelating agent. The fluorine-containing cleaning liquid according to claim 12, wherein the corrosion inhibitor is selected from the group consisting of benzotriazole, benzoic acid, polyacrylic acid, and 1,3-(hydroxyethyl)-2,4,6- One or more of the triphosphonic acids; the chelating agent is an organic compound containing a plurality of functional groups. The fluorine-containing cleaning solution according to claim 12, wherein the chelating agent is selected from the group consisting of glycolic acid, malonic acid, citric acid, iminodiacetic acid, ammonia triacetic acid, triethanolamine, ethylenediaminetetraacetic acid, and o One or more of hydroquinone, gallic acid, salicylic acid, pentamethyldiethylenetriamine, sulfamic acid, and sulfosalicylic acid.