WO2009052706A1

WO2009052706A1 - A rinse solution for removal of plasm etching residues

Info

Publication number: WO2009052706A1
Application number: PCT/CN2008/001757
Authority: WO
Inventors: Bing Liu; Libbert Hongxiu Peng; Joey Hao Yu
Original assignee: Anji Microelectronics (Shanghai) Co., Ltd
Priority date: 2007-10-19
Filing date: 2008-10-20
Publication date: 2009-04-30
Also published as: CN101412949A; CN101827926A

Abstract

A rinse solution for removal of plasm etching residues includes fluoride, organic amine, solvent and water. The rinse solution can be used to remove plasm etching residues on the metal, via and pad wafers, and the rate of corrosion to non-metallic material such as SiO2, PETEOS, silicon and low dielectric material and some metallic material such as Ti, Al and Cu is low.

Description

Plasma etching residue cleaning liquid

The present invention relates to a cleaning fluid in a semiconductor manufacturing process, and in particular to a plasma etching residue cleaning fluid. 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 will harden the photoresist polymer during the wetting step, 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 (thousand ash ashing and wet etching). The first step uses dry ashing to remove most of the photoresist layer (PR). The second step utilizes the corrosion inhibitor composition wet etch/clean process to remove the remaining photoresist layer. The specific steps are typically rinse cleaning/rinsing/deionized water rinsing. In this process, only the residual polymer photoresist layer and the inorganic material can be removed, and the damaged 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-hydroxyl amine) cleaning solution and fluoride cleaning solution. Among them, the first two types of cleaning liquids need to be cleaned at high temperatures, generally between 60 Ό and 80 ° C, and there is a problem that the corrosion rate of the metal is large. While existing fluorinated cleaning solutions can be cleaned at lower temperatures (room temperature to 50 Torr), there are still various disadvantages. For example, the corrosion of metal and non-metal substrates cannot be controlled at the same time, and the size of the channel features can be changed after cleaning, thereby changing the semiconductor structure; the etching rate is large, so that the cleaning operation window is relatively small.

1

Confirmation The cleaning solution composition disclosed in US 6, 828, 289 comprises: an acidic buffer, an organic polar solvent, a fluorine-containing substance and water, and having a pH between 3 and 7, wherein the acidic buffer is composed of an organic carboxylic acid or a plurality of The acid is composed of the corresponding ammonium salt, and the composition ratio is between 10:1 and 1:10. US 5,698, 503 discloses a fluorine-containing cleaning liquid, but a large amount of ethylene glycol is used, and the viscosity and surface tension of the cleaning liquid are large, thereby affecting the cleaning effect. US 5, 972, 862 discloses 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 7 to; Ll, because the cleaning effect is not very stable There are various problems.

Therefore, in order to overcome the defects of the existing cleaning liquid and adapt to new cleaning requirements, such as a more environmentally friendly, low defect level, low etching rate and a large operating window, it is urgent to seek a new cleaning liquid. Summary of invention

The technical problem to be solved by the invention is to overcome the existing corrosion rate of the plasma etching residue cleaning liquid, the corrosion of the metal and the non-metal can not be controlled at the same time, the cleaning window is small, the cleaning ability is insufficient, and the cleaning effect is unstable. Providing a plasma etching residue cleaning liquid which has a strong cleaning ability and a small corrosion rate, can simultaneously control metal and non-metal corrosion, has a large cleaning window, and has a stable cleaning effect.

The plasma etch residue cleaning solution of the present invention contains fluoride, an organic amine, a solvent, and water. Wherein, the fluoride is preferably selected from the group consisting of hydrogen fluoride or a salt formed by hydrogen fluoride and a base, preferably hydrogen fluoride (HF), ammonium fluoride (NH ₄ F), ammonium hydrogen fluoride (H4HF ₂ ), tetramethylammonium fluoride. One or more of (N(CH ₃ ) ₄ F) and trishydroxyethylammonium fluoride (N(CH20H) ₃ HF). The base is preferably selected from the group consisting of ammonia water, quaternary ammonium hydroxides and alcohol amines. The content of the fluoride is preferably from 0. 01 to 20% by mass. Wherein, the organic amine is preferably one or more of an organic amine having a hydroxyl group, an amino group and a carboxyl group. The hydroxyl group-containing organic amine is preferably an alcohol amine such as ethanolamine, diethanolamine, triethanolamine, isopropanolamine, N,N-dimethylethanolamine and N-methyldiethanolamine; The organic amine is preferably an organic polyamine such as diethylenetriamine, pentamethyldiethylenetriamine and a polyethene polyamine; the carboxyl group-containing organic amine is preferably an amino group-containing organic acid such as 2- Glycine, 2-aminobenzoic acid, iminodiacetic acid, ammonia triacetic acid and ethylenediaminetetraacetic acid. Among them, one or more of pentamethyldiethylenetriamine, iminodiacetic acid, and triethanolamine are more preferable. The content of the organic amine is preferably from 0.1 to 35% by mass. The presence of organic amines contributes to pH stability and improves the stability and reproducibility of the cleaning process.

Among them, the solvent is preferably one or more of sulfoxide, sulfone, imidazolium, pyrrolidone, imidazolidinone, amide and ether. The sulfoxide is preferably one or more of dimethyl sulfoxide, diethyl sulfoxide and methyl sulfoxide; the sulfone is preferably methyl sulfone, ethyl sulfone and sulfolane. One or more of the above; the imidazolium is preferably 2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, and 1,3-diethyl-2-imidazolidine One or more of the ketones; preferably the pyrrolidone is 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 one or more of ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, propylene glycol monodecyl ether, dipropylene glycol monoalkyl ether and tripropylene glycol monoalkyl ether. Wherein, the ethylene glycol monodecyl ether is preferably one or more of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether; The monodecyl ether is preferably one or more of diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether; the propylene glycol monoalkyl ether is preferably Propylene glycol monomethyl ether, propylene glycol monoethyl ether and One or more of propylene glycol monobutyl ether; the dipropylene glycol monoalkyl ether is preferably one or more of dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether and dipropylene glycol monobutyl ether; The tripropylene glycol monodecyl ether is preferably tripropylene glycol monomethyl ether. The content of the solvent is preferably 35 to 80% by mass.

Wherein, the content of the water is preferably 10 to 45% by mass.

The cleaning solution of the present invention may further comprise other conventional additives in the art, such as metal preservatives (e.g., copper preservatives: benzotriazole; and aluminum preservatives: polyacrylic acid).

The cleaning liquid of the present invention can be obtained by simply mixing and mixing the above components. The cleaning solution of the present invention can be used over a wide temperature range, generally in the range of room temperature to 55 ° C, and can be applied to various cleaning methods such as batch immersion, batch rotary, and single-piece rotary. The reagents and materials used in the present invention are commercially available.

The positive progress of the invention is as follows: The cleaning liquid of the invention has strong cleaning ability, and can clean the metal wire, the channel (Via) and the metal pad (Pad) wafer, effectively remove the plasma etching residue, and Non-metallic materials (such as Si0 ₂ , ion-enhanced tetraethoxysilane silicon dioxide (PETE0S), silicon and low dielectric materials) and metal materials (such as Ti, A1 and Cu) have lower corrosion rates. Simultaneously control the corrosion of metals and non-metals. In addition, the cleaning liquid of the present invention can be applied to a batch batch, a batch-spray, and a single wafer tool, and has a large operation window. Summary of the invention

The invention is further illustrated by the following examples, which are not intended to limit the invention. Examples 1 to 31

Table 1 shows Examples 1 to 31 of the plasma etching residue cleaning liquid of the present invention, and the cleaning liquids of the respective examples were prepared by mixing the components according to the formulation in the table.

Table 1 Plasma etching residue cleaning solution of the present invention 1~31

Effect embodiment

Table 2 shows the formulations of the cleaning solutions 1 and 2 of the present invention. According to the formulation of Table 2, each component can be simply mixed and mixed to prepare each cleaning solution.

The formulation of the cleaning solutions 1 and 2 of the present invention and their cleaning effect and corrosion rate

Clean the metal wire, channel and metal pad with cleaning solutions 1 and 2, and test each cleaning solution. Corrosion rate of metallic aluminum and non-metal (PETE0S).

Test method for metal corrosion rate of cleaning 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 which has been previously kept at a temperature of 35 ° C for 30 minutes;

3) The 4*4 cm aluminum blank silicon wafer was taken out, washed with deionized water, dried with high purity nitrogen gas, and then tested for resistance value (Rs2) of 4*4 cm aluminum blank silicon wafer by 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 above resistance value and soak time into a suitable program to calculate the corrosion rate. Non-metallic corrosion rate test method for cleaning solution:

1) testing the thickness (T1) of the 4*4cm PETE0S silicon wafer using the Nanospec6100 thickness gauge;

2) soaking the 4*4craPETE0S silicon wafer in a solution that has been previously thermostated to 35 Torr for 30 minutes;

3) Take out the 4*4cm PETE0S silicon wafer, wash it with deionized water, dry it with high purity nitrogen, and test the thickness (T2) of 4*4cm PETE0S silicon wafer with Nanospec6100 thickness gauge;

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

5) Enter the above thickness value and soaking time into a suitable program to calculate the corrosion rate. Table 3 shows the formulations of the cleaning solutions 1 and 2 of the present invention, as well as the cleaning effect and corrosion rate.

Table 3 Cleaning effect and corrosion rate of cleaning liquids 1 and 2 of the present invention

Non-metal (tetraethoxy)

Metal (aluminum) rot

Silane dioxide

Etching rate Different types of wafer cleaning results

Corrosion of silicon, PETE0S)

(A/min)

Wash rate (A/min)

Liquid first first

Second 30

30 30 30 channels Golden Brain Minute Minutes

Minute minute

1 1.75 0.83 Clean, no change

0.2 0.15 clean, no corrosion clean, no decay candlestick size

2 1.20 0.75 Clean, no change

0.63 0.68 Clean, not corroded, no corrosion path size It can be seen from Table 3 that the cleaning liquid of the present invention does not substantially corrode metals (such as metal aluminum) and non-metals (such as PETEOS) used in semiconductor fabrication, and the etching rate is close to or lower than that normally required by the semiconductor industry. 2 angstroms per minute. Cleaning the plasma etch residue with the cleaning solution in Table 2 revealed that the plasma etch residue was removed and substantially no corrosion of metals and non-metals.

Claims

Rights request

A plasma etching residue cleaning liquid comprising: a fluoride, an organic amine, a solvent, and water.

2. The plasma etching residue cleaning solution according to claim 1, wherein: the fluoride is selected from the group consisting of hydrogen fluoride, ammonium fluoride, ammonium hydrogen fluoride, tetramethylammonium fluoride, and trishydroxyethyl fluoride. One or more of ammonium salts.

The plasma etching residue cleaning solution according to claim 1, wherein the fluoride content is 0.01 to 20% by mass.

The plasma etching residue cleaning solution according to claim 1, wherein the organic amine is one or more of an organic amine having a hydroxyl group, an amino group and a carboxyl group.

The plasma etching residue cleaning liquid according to claim 4, wherein: the hydroxyl group-containing organic amine is an alcohol amine; and the amino group-containing organic amine is an organic polyamine; The organic amine of the carboxyl group is an amino group-containing organic acid.

6. The plasma etching residue cleaning solution according to claim 5, wherein: the alcohol amine is ethanolamine, diethanolamine, triethanolamine, isopropanolamine, N,N-dimethylethanolamine, and One or more of N-methyldiethanolamine; the organic polyamine is one or more of diethylenetriamine, pentamethyldiethylenetriamine, and polyethenepolyamine; The organic acid of the amino group is one or more of 2-aminoacetic acid, 2-aminobenzoic acid, iminodiacetic acid, aminotriacetic acid, and ethylenediaminetetraacetic acid.

7. The plasma etch residue cleaning solution according to claim 1, wherein the organic amine is present in an amount of 0.1 to 35% by mass.

8. The plasma etch residue cleaning solution according to claim 1, wherein: The solvent is one or more of sulfoxide, sulfone, imidazolidinone, pyrrolidone, imidazolidinone, amide and ether.

9. The plasma etch residue cleaning solution according to claim 8, 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-imidazolium And one or more of 1,3-diethyl-2-imidazolium; the pyrrolidone is N-methylpyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone and N-hydroxyl One or more of ethyl pyrrolidone; the imidazolidinone is 1,3-dimethyl-2-imidazolidinone; the amide is dimethylformamide and/or dimethylacetamide The ether is one or more of ethylene glycol monodecyl ether, diethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether, and tripropylene glycol monoalkyl ether.

The plasma etching residue cleaning solution according to claim 9, wherein the ethylene glycol monoalkyl ether is ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol single One or more of butyl ether; the diethylene glycol monodecyl ether is one or more 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 monodecyl ether is dipropylene glycol monomethyl ether, dipropylene glycol One or more of monoethyl ether and dipropylene glycol monobutyl ether; the tripropylene glycol monoalkyl ether is tripropylene glycol monomethyl ether.

The plasma etching residue cleaning solution according to claim 1, wherein the solvent is contained in an amount of 35 to 80% by mass.

The plasma etching residue cleaning liquid according to claim 1, wherein the water is contained in an amount of 10 to 45% by mass.