KR100349816B1 - Micro Machining Surface Treatment Agent - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

A microfabricated surface treatment agent used to wet remove, etch and clean silicon surfaces in silicon during the manufacture of semiconductor devices.

2. The technical problem to be solved by the invention

Low particle quality of the treatment agent, wettability to the silicon surface and permeability to fine intervals, smoothing of the silicon surface, low particle adhesion to the silicon surface, stability of the treatment agent, high purity, cleaning the silicon surface or improving the etching effect of the oxide film .

3. Summary of Solution to Invention

A fine surface treatment agent having excellent infiltration property by containing a hydrofluoric acid containing a hydrocarbon-based nonionic surfactant having an HLB value of 7 to 17.

4. Important uses of the invention

Surface treatment agent in semiconductor device manufacturing process.

Description

Micro Machining Surface Treatment Agent

The present invention relates to a microfabricated surface treatment agent and, more particularly, to a microfabricated surface treatment agent used for wet removal, etching, and cleaning of the silicon surface of silicon in the manufacture of semiconductor porcelain.

Although hydrofluoric acid is used as a surface treatment agent (hereinafter abbreviated as treatment liquid) in semiconductor device manufacturing, it is necessary to have high purity and high cleanliness from the purpose of treatment, but for high integration of semiconductors, high performance, and production of products for high raw materials Again, full and comprehensive surface treatment was required.

Specifically, for example, a surface treatment process for removing an oxide film on a silicon substrate is an important process for controlling the mission of subsequent microcircuit formation, and the chemical action must be performed completely homogeneously on the surface power of the silicon substrate. It is necessary to ensure that the cleaning action is completed to make the extremely active surface flawless and also to the extremely smooth clean surface.

For this reason, the importance of hydrofluoric acid wetting well on the surface treatment must be emphasized.

Also, in the etching process to form the LSI circuit, the pattern is highly integrated and complicated, and the hydrofluoric acid is well infiltrated into the microgap (groove), and if the chemical cleaning does not perform a complete cleaning operation in the groove, Homogeneity and perfect micromachining cannot be achieved. That is, the function of infiltration and permeability is extremely important for the treatment liquid.

In the conventional pattern formation, the grooves were washed with sulfuric acid-hydrogen peroxide water, hydrochloric acid-hydrogen peroxide water, or ammonia water-hydrogen peroxide water, but it is necessary to remove the oxide film formed at that time. Hydrofluoric acid, however, is a low-viscosity low surface tension (8.6 dyn / cm) liquid at 100%, but as the dilution progresses, it approaches the surface tension of water. The contact angle of the hydrofluoric acid to the silicon surface is 58 to 76 degrees, i.e., a liquid that is difficult to get wet. The surface tension is also 50 to 73 dyn / cm.

In this way, when the surface tension or contact angle of dilute hydrofluoric acid is large, it is difficult to treat the micromachined surface called etching cleaning without uniformly penetrating into the fine grooves. Table 1 shows the data of surface tension and contact angle. Super pure data is also shown for reference. However, Table 1 shows the surface tension and contact angle of ultrapure water and hydrofluoric acid.

In order to evaluate the invasiveness to the silicon surface, the contact angle of the treatment agent dropped on the silicon surface was measured by the droplet method. In addition, surface tension was performed by the vertical plate method.

It is needless to say that the surface tension is an action that acts on the gas-liquid interface, and the contact angle is an action that acts on the solid-liquid interface.

As described above, infiltration is important as a function of the treatment liquid. In order to impart infiltration, it is necessary to add a surfactant, but depending on the type of the surfactant, the activator may be adsorbed onto the treated surface (silicon oxide film) and thus the oxide film cannot be removed.

Measures to effectively improve the invasiveness without adversely affecting the essential function of the treatment liquid have not been proposed or solved.

The chemical structure and surfactant mechanism of the surfactants vary widely, and the treatment liquid to which any surfactant is added is suitable as a micro-processing surface treatment agent (hereinafter abbreviated as treatment agent) in the semiconductor manufacturing process, and the presence of the surfactant There is a need to look at the overall impact on the properties of the treatment.

The present inventors have found out the following problems by examining in detail the phenomenon occurring when the surfactant is added to the treatment liquid.

1. The surface tension of the treatment agent is easily lowered by the addition of the surfactant, but the contact angle to the silicon surface is not necessarily reduced. That is, the treatment agent does not infiltrate the silicon surface well or penetrate the microgap well.

2. When circulating filtration is used in which the surfactant is not dissolved in the treatment liquid and is well used to remove particles in the liquid in the semiconductor manufacturing process, the surfactant is adsorbed and trapped on the filter, and thus the activity is often lowered. (Surface tension and contact angle increase). Moreover, even if it melt | dissolves in a process liquid immediately after adding a surfactant, when surfactant passes for a long time, surfactant activity and a process liquid may separate and activity may fall.

3. In some cases, the addition of surfactant increases the number of particles in the treatment agent, and an increase in impurities such as alkali metal, alkaline earth metal and heavy metal, which are said to adversely affect the semiconductor element.

This phenomenon is undesirable because it increases the risk of particle adhesion on the silicon surface or micromachining intervals and impairs the performance of the semiconductor device due to impurities.

4. Excessive addition of surfactants often results in excessive micelles in the treatment liquid and causes various obstacles to the micromachining process.

(A) Micelles of surfactant adhere to the etching surface, causing etching spots and etching failures.

(B) Micelles may adhere to the silicon surface drawn from the processing liquid and cause stains, or may cause haze such as scattering of laser light when the wafer surface is observed using a wafer inspection apparatus.

(C) Excessive addition of surfactants interferes with foaming in the treatment of wastewater.

As mentioned above, although it is necessary to improve the invasiveness of a treatment agent by addition of surfactant, the risk which adversely affects the important function of a treatment agent also arises simultaneously.

The cleaning process using hydrofluoric acid is very important in the semiconductor manufacturing process, and in particular, the smoothness of the cleaning surface is attracting attention as an extremely important factor for the submicron device.

However, the surface of silicon wafers cleaned with hydrofluoric acid was observed at atomic level using atomic force microscopy (AFM), indicating that the smoothness was impaired.

In addition, when the silicon wafer is etched using buffered hydrofluoric acid (a mixed acid obtained by mixing hydrofluoric acid and ammonium fluoride in an appropriate ratio), roughness occurs on the surface, but a technique for maintaining smoothness by blending an appropriate surfactant is, for example, Japan. It is developed by Japanese Patent Laid-Open No. 63-283028 or Japanese Patent Laid-Open No. 3-179737.

However, even if the surfactant added to the buffered hydrofluoric acid is added to hydrofluoric acid, the effect is not obtained. On the contrary, depending on the silicon wafer, for example, in the case of P-type (100) wafer, the surface of the silicon becomes rough after 30 minutes. This occurrence has been confirmed by AFM.

Such surface defects are a serious obstacle in the formation of shallow junctions, for example, in highly integrated circuits. Therefore, in the cleaning using hydrofluoric acid, it is very important to develop a means for imparting infiltration to obtain surface smoothness.

There are very many kinds of surfactants, and there are hydrocarbon-based surfactants and fluorine-based surfactants. The surfactants are cationic, anionic, amphoteric and nonionic, and they are hydrocarbon-based like Japanese Patent Application Laid-Open No. 1-1183824. It does not mean that any surfactant may be sufficient as it.

Among the active agents used in Japanese Patent Application Laid-Open Nos. 58-55323 and 58-42019, surfactants that increase the number of particles adhering to the silicon surface or roughen the silicon surface, such as primary amine salts and secondary grades Amine salts, tertiary amine salts, quaternary ammonium salts and the like are contained and are not suitable for use as an etching cleaner for silicon and silicon oxide films.

In addition, dodecylbenzenesulfonic acid used in Japanese Patent Application Laid-Open No. 63-230800 has a high bubble and a problem that is likely to cause an etching defect in the semiconductor manufacturing process.

In addition, Japanese Patent Application Laid-Open No. Hei 4-16011 describes a method of etching a silicon oxide film formed on the bottom surface of micropores of 1 to 5 탆 by adding a nonionic surfactant to hydrofluoric acid. Examples of nonionic surfactants include polyethylene glycol lauryl ether, polyethylene glycol alkyl phenyl ether, and polyethylene glycol fatty acid esters, but only one example of adding 0.1% by volume of polyethylene glycol lauryl ether to 1:20 dilute hydrofluoric acid is illustrated. not.

Currently, high integration has progressed, and the line width to be etched or etched is less than 1 μm. In Japanese Patent Application No. 4-16011, it is not possible to cope with the treatment agent in the present stage of high integration, and it is necessary to select more precisely the surface tension, the contact angle, and the characteristics described in the present invention. In -160115, it is not possible to select a surfactant suitable for the manufacture of highly integrated semiconductors, and is not very suitable as an etchant and cleaning agent.

In addition, IPA (isopropyl alcohol), etc., may be used to reduce the surface tension by adding about 10%, but in this case, it may cause problems during drainage, so it is not suitable for this purpose unless the surfactant is effective in small amounts. .

When used again, for example, the hydrogen fluoride concentration is often used as hydrofluoric acid of 0.5% by weight or 5% by weight.

However, manufacturing and selling such hydrofluoric acid is not economical, and therefore, it is preferable that the production does not change even if the hydrofluoric acid is produced at a concentration of 50% by weight and diluted at the time of use.

MEANS TO SOLVE THE PROBLEM In order to solve the problem of a processing agent, this inventor carried out the experiment by careful consideration from the viewpoint of extremely careful technical search and green technology. However, surfactants are used for an extremely wide range of uses and various conditions, and they are classified into hydrocarbon-based surfactants and fluorine-based surfactants, and can be further divided into cationic, anionic, amphoteric and nonionic.

However, there are many groups of compounds in each class, and their interfacial behavior is characteristic. In order to select the surfactant suitable for the objective of this invention, the surfactant which irradiated and satisfy | fills each item of following (1)-(6) was selected. Again, the main purpose of using these surfactant-added treatment agents is to etch the silicon oxide film, or to wash the silicon wafer with sulfuric acid-hydrogen peroxide, hydrochloric acid-hydrogen peroxide or ammonia-hydrogen peroxide water, and then again on the front or etching of the silicon wafer during ultrapure water cleaning. Removal of the oxide film formed in the formed grooves.

At this time, the water-repellent property on the wafer confirmed whether or not the original purpose of (7) was impaired due to the addition of the surface treating agent.

(1) low particulateness of the treatment agent

(2) Infiltration into the silicon surface of the treatment agent and permeability into the fine gap

(3) Smoothing of silicon surface

(4) Low particle adhesion to silicon surface

(5) Stability of treatment agent

(6) high purity of treatment agent

(7) cleaning of silicon surface or etching effect of oxide film

The following examination means was used to quantitatively evaluate the adequacy of the surfactant added to the treatment liquid for the treatment agent satisfying the above seven conditions. The treatment liquid used for the test was 0.5% by weight, 5% by weight and 50% by weight hydrofluoric acid.

(1) low particulateness of the treatment agent

One of the important points required as a treatment agent used in the micromachining surface treatment process is low particle size.

This is because the defect of etching by the particle becomes a big factor in the reduction of the quantity of the product with respect to the raw material in semiconductor manufacturing. As shown in FIG. 1, there is a surfactant that can reduce the number of particles by adding a surfactant to the treatment liquid and circulating filtration. However, the mechanism of abatement reduction is unknown. 1 is a diagram showing the relationship between the surfactant concentration and the liquid particles, the HF concentration is 0.5%.

In addition, even when circulating filtration with the addition of a surfactant, the particles in the treatment liquid do not decrease and increase inversely. Such a surfactant is not suitable for this purpose.

Various surfactants (hydrocarbon-based, fluorine-based and each ion type (non-ion, cation, anion, zwitterion)) were investigated to find a suitable surfactant for this purpose.

Moreover, about the same compound, about the molecular weight differs, it was described as A, B, C .... The results are shown in Tables 2 to 14. However, the following symbols in Tables 2 to 14 each indicate the following.

A: hydrocarbon-based nonionic surfactant

B: hydrocarbon anionic surfactant

C: hydrocarbon-based cationic surfactant

D: hydrocarbon type amphoteric surfactant

E: fluorine-based nonionic surfactant

F: fluorine-based anionic surfactant

G: fluorine-based cationic surfactant

H: fluorine-based amphoteric surfactant

The number of particles was assumed to be a surfactant in which 0.5 μm or more of particles became 10 particles / m or less, satisfying this purpose. 1 shows the relationship between the surfactant concentration and the liquid particles.

In addition, the particles in the treatment liquid were laser-scattered liquid fine particles counter using the fluorine resin filter with a 0.1 μm pore diameter to determine the number of particles in the treatment agent when 24 cycles of filtration were performed at a flow rate of 750 kg / m ² · hr. Was measured.

(2) Infiltration into the silicon surface of the treatment agent and permeability into the fine gap

Invasiveness of the silicon surface when the silicon wafer was immersed in the treatment agent when the contact angle to the silicon surface of the treatment agent was 50 degrees or less, and the surface tension was 45 dyn / cm or less. This is bad.

In addition, the cross-sectional photograph using an electron microscope and the atomic force microscope (AMF) confirmed that the permeability to fine patterns of 10 micrometers or less is bad and the etching defect of a silicon oxide film arises.

Surfactants added to the treatment liquid with a contact angle of 50 degrees or less and a surface tension of 5 dyn / cm or less are present in a large number of surfactants in the hydrocarbon-based fluorine group, but circulating filtration and damage caused by excessive addition A surfactant suitable for this purpose is satisfied to satisfy this condition at a concentration not exceeding 1000 ppm.

This item is investigated about the surfactant which passed the item of (1) here, and the result is shown to Table 15-23. The symbols A to H of Tables 15 to 23 are as described above.

(3) smoothness of silicon surface

It is said that the smaller the unevenness of the sub-nanome on the surface of the silicon wafer, i.e., the smaller the micro raffnes, the higher the reliability and the higher the device. The roughness of the silicon surface was measured by immersing the silicon wafer in the treatment agent for 100 minutes and then using an atomic force microscope (AFM) to treat the silicon surface with a centerline average roughness (Ra) of 0.3 nm (3 Å) or less. I was satisfied.

Table 24-Table 30 show the result of having investigated this item about surfactant which satisfy | fills the item of (1) (2) here.

However, symbols of A to H in the above tables are as described above.

(4) Low particle adhesion to silicon surface

As described in (2), the particles on the wafer have a fatal blow in the semiconductor process. The deposition of particles on the wafer was measured by the number of particles adhering to the silicon surface in the wafer inspection system.

The number of particles on the wafer surface treated with hydrofluoric acid without a surfactant and hydrofluoric acid added was compared. Hydrofluoric acid treatment is the final step in etching and cleaning, so the treatment liquor with the treatment agent remains ultrapure water cleaning. For this reason, low particle adhesion is a very important item. The number of adhered particles satisfying this object was set to 100 or less particles having a particle size of 0.3 to 0.5 탆 on 5 inch bare silicon.

2 shows the relationship between the surfactant concentration and the attached particles. Also, from the relationship between the surfactant concentration and the particle of FIG. 1, the surfactant concentration is effective from a very small amount, but when the concentration is increased (over 1000 ppm), the particles in the treatment agent and the particles adhering to the silicon surface increase rapidly. have. As such, the amount of the surfactant added is preferably 1000 ppm or less.

Table 31-Table 33 show the result of having investigated this item about surfactant satisfied in the item of (1)-(3) here.

However, symbols of A to H in the table are as described above.

(5) Stability of treatment agent

Six months after the adjustment of the treatment agent that satisfies the above four conditions, four conditions were measured again to confirm whether or not a change occurred.

Particle number, surface tension, contact angle, wafer attached particle number, and wafer surface roughness were measured for the surfactant satisfying the item (4), but the results were unchanged upon adjustment.

(6) high purity of treatment agent

The high purity was analyzed by adding the surfactant and analyzing its components to determine whether there was an increase in alkali metals or alkaline earth metals and heavy metals that adversely affect the semiconductor process. Impurity analysis was carried out 6 months after the adjustment of the surfactant satisfying the item (5), and it was confirmed that all the surfactants did not increase the alkali metals or alkaline earth metals and heavy metals which adversely affect the semiconductor process. .

The final condition that must be satisfied in the semiconductor process for a surfactant that satisfies all of the above six conditions [(1) to (6)], namely (7) etching of the main purpose silicon oxide film in which hydrofluoric acid is used for this application. Alternatively, a surfactant was irradiated to remove the oxide film formed on the front surface of the silicon wafer during the ultrapure water cleaning or the groove formed by etching again when washed with sulfuric acid-hydrogen peroxide water, hydrochloric acid-hydrogen peroxide water or ammonia-hydrogen peroxide water.

(7) cleaning the silicon surface or etching the oxide film

The primary purpose of this treatment agent is to remove the native oxide film on the silicon surface. The growth of natural chemistry occurs not only in the air, but also in the cleaning of ultrapure water rinsing, again in sulfuric acid-hydrogen peroxide, hydrochloric acid-hydrogen peroxide or ammonia-hydrogen peroxide.

The oxide film produced at this time must be removed with this treatment agent, but some surfactants inhibit the removal of the oxide film strongly adsorbed on the silicon oxide film surface. Whether or not the natural oxide film on the silicon surface was removed can be confirmed by immersing the silicon oxide film grown by the wet method in the treatment agent for 1 minute, rinsing with ultrapure water for 1 minute, and measuring the contact angle of the ultrapure water dropped on the substrate. have.

As a result, the contact angle of the ultrapure water on the submerged ultrapure rinsed substrate can be confirmed by returning to 72 °, which is the contact angle of water on the silicon substrate. The results are shown in Tables 34 to 36.

However, symbols of A to H in the above tables are as described above.

The contact angle of ultrapure water dropped on the silicon oxide film formed by the wet method is 12 degrees, and the ultrapure water spreads thinly on the silicon oxide film.

However, it can be seen that the ultrapure water on the silicon plane from which the oxide film was removed with the treatment agent formed round droplets, the contact angle was 72 degrees, and the silicon oxide film was removed with the treatment agent.

However, some of the surfactants cover the silicon oxide film and inhibit the removal of the oxide film to hydrofluoric acid. Therefore, the contact angle of ultrapure water may not be around 72 degrees even if it immerses for 1 minute in a processing agent.

The surfactant is adsorbed on the surface of the oxide film to prevent etching of the oxide film. Instead, it becomes a water-repellent surface peculiar to the fluorine-based surfactant. When the contact angle is measured by ultrapure water, the value is more than 85 degrees. Hydrocarbon surfactants have extremely high hydrophilicity, are strongly adsorbed with the native oxide film on the wafer surface, cannot be completely removed by HF solution, and the contact angle is reduced to about 50 degrees because the oxide film remains. In the case of the natural oxide film grown by the dry method, the wet grown film was commercially available because the contact angle of water on the oxide film was large (36 degrees) and it was difficult to determine whether the oxide film had been removed.

As a result of studying a surfactant for satisfying all the above seven conditions, it was found that only one kind of nonionic surfactant and its congestion type were suitable for the purpose.

The present invention has been completed based on these numerous new discoveries. Investigation of the properties of the surfactant suitable for this purpose revealed that HLB was in the range of 7 to 17.

It is well known that the HLB value of a surfactant is Hydrophile-Lipophile Balance of the chemical structure, and the numerical value which showed the balance of the hydrophilicity and lipophilic property of surfactant. However, the discovery that the contact angle with respect to the silicon surface depends on the HLB value is still unknown and was the first to be discovered in the present invention.

The microfabricated surface treating agent of the present invention is prepared by mixing hydrofluoric acid with one or two or more of the above-described specific surfactants in nonionic surfactants such that the following HLB is in the range of 7 to 17. Hydrofluoric acid refers to an aqueous hydrofluoric acid solution containing 0.01 to 55% by weight of hydrogen fluoride.

Nonionic surfactants have a polyoxyalkyl as the main structure and a group of chemical structures such as ether type, ester type, or glycol type, but the detailed structure is extremely rich and the molecular structure, that is, molecular weight, carbon number, substituents, etc. It is usually represented by a common chemical name. Therefore, the characteristics and behavior of each surfactant in the treatment agent cannot be characterized with chemical structures.

However, it is extremely important to characterize the effect, so we searched for it from all angles.

As a result, it was found that there was extremely obvious chemical structure regularity. It is the relationship between the contact angle with respect to the silicone surface of surfactant addition agent, and the HLB value of surfactant.

Table 37 shows the results of measuring contact angles with respect to the silicon surface for surfactants having a series of HLB values.

From these results, it was found that a very small area of contact angle exists in a range of HLB values. As a result, even in the compound group described above, the HLB value in which the contact angle is 50 degrees or less is in the range of 7 to 17. When the HLB value is less than 7 or 18 or more, the contact angle exceeds 50 degrees and the silicon surface does not get wet.

However, Table 37 shows the relationship between the HLB value and the contact angle, and * in the table indicates the mixing system.

In addition, the HLB value hangyeongwoo caustic property is established by mixing the HLB of the surfactant _A W _A (g) _B and HLB surfactants W _B (g) _AB HLB of the mixed system of the formula (1),

HLB _AB- (HLB _A XW _A + HLB _B XW _B ) / (W _A + W _B )

It is known that consciousness is established.

In the mixed system, the dependence of the contact angle and the HLB was verified, and it was found that there was a very small area of the contact angle.

Table 38 shows the test results obtained by calculating the HLB value and the number of particles. From these results, it was also found that when the HLB value is 7 or more, the number of particles can be reduced, and the surfactant addition treatment agent having an HLB value of less than 7 cannot reduce the particle number of the treatment agent even by performing circulating filtration.

However, Table 38 will investigate the number of particles after circulating filtration.

The mechanism by which the very fine particles are filtered out in the presence of surfactants is thought to be related to the micelle formation of the surfactant molecules, but this was the first time that they were also dependent on the HLB value of the surfactants.

As mentioned above, the new discovery facts are summed and the range of HLB value of surfactant suitable as a processing agent is calculated | required. That is, the HLB value is in the range of 7 to 17, preferably in the range of 10 to 15, by mixing one or two or more kinds of nonionic surfactants.

Illustrative nonionic surfactants used in the present invention are ester higher alcohol condensates, higher fatty acid condensates and alkylphenol condensates of glycols. Specifically, for example:

Polyoxyethylene higher alcohol ether (HLB value 10.5, 12.1, 13.3)

C ₁₂ H _25- C ₁₄ H ₂₉ O (CH ₂ CH ₂ O) _n H

Polyoxyethylene Oleic Acid Ester (HLB Value 9, 12, 14, 16)

C ₁₇ H ₃₃ OO (CH ₂ CH ₂ O) _n H

Polyoxyethylene lauryl ether (HLB value 8, 9.7, 10, 10.5, 12.1, 13.8, 13. 9, 14, 15.3, 16, 16.3, 17, 17.3, 19, 20)

C ₁₂ H ₂₅ O (CH ₂ CH ₂ O) _n H

Polyoxyethylene nonylphenyl ether (HLB value 7.8, 9.2, 10.8, 12.2, 12.4, 13.7, 14.5, 15.1, 15.5, 17, 17.5, 18.2, 18.9)

Formula 2.

Polyoxyethylene octylphenyl ether (HLB value 9, 11, 12, 13.1, 14, 15, 18, 19, 20's)

Formula 3.

Polyoxyethylene alkylallyl ether (HLB value 8, 8.8, 10.0, 12, 13, 13.6, 14, 15, 16, 16.2, 17)

Etc. are preferable. R represents an alkyl group here.

These surfactants are used in one kind or in a mixture of two or more kinds, and are also used in solid form or in liquid form. The addition amount is 10-1000 ppm with respect to the whole composition.

Since hydrofluoric acid of the treatment agent of the present invention is often used at a concentration of 5% by weight or 0.5% by weight of dilute hydrofluoric acid, 10 to 1000 ppm may be added to the desired hydrofluoric acid concentration in advance, and the addition of a surfactant For example, when the concentration is used at 250 ppm, the surfactant of the present invention is added to 50 ppm by weight of hydrofluoric acid to have a concentration of 2500 ppm or 25000 ppm, and the present invention is prepared by circulating filtration, and the product is 5% by weight and 0.5% by weight of fluoride, respectively. You may dilute in hydrochloric acid. In this case, the same activity as that prepared by adding 250 ppm of the surfactant of the present invention was obtained, and the native oxide film on the silicon surface and the native oxide film in the grooves after the pattern formation were completely removed. Again, the treatment agent analyzed the metal impurities that are harmful during the micro-processing surface treatment, it was confirmed that these impurities are not increased compared to the treatment liquid and high purity is maintained.

When the silicon surface was etched using the treatment agent of the present invention, the number of particles deposited on the etching surface was small.

In addition, the roughness of the etching surface when the silicon wafer was immersed in the treatment agent of the present invention for 100 minutes was significantly improved compared to hydrofluoric acid without addition of the surfactant of the present invention.

The surface tension, the contact angle and the number of particles were measured after 3 months of storage of the treatment agent of the present invention, but did not change with the preparation. In addition, the above seven conditions were satisfied even if they were subjected to circular filtration.

From this, it was confirmed that this treatment agent has long term stability.

The microfabricated surface treatment agent of the present invention is capable of finer etching processing and more uniform etching in order to improve the infiltration to the silicon surface and to increase the degree of integration, and to clean the silicon surface again.

Even if it is stored for a long time, its performance does not change at all, and its performance does not change even if it is filtered. Therefore, high uniformity of micromachining is ensured.

In particular, since there are few fine particles in the treatment agent and the infiltration into the etching surface is good again, when the silicon surface is etched, the adhesion of the particles on the etching surface can be reduced and the etching surface can be smoothly completed again.

EXAMPLE

Next, an Example is given and this invention is demonstrated in detail again.

(Example 1.)

Add 200 ppm of surfactant to 0.5, 5.0, and 50% by weight hydrofluoric acid and its surface tension, contact angle to silicon and number of particles (particles of 0.5 μm or more) and again 0.5, 5.0, and 50% by weight of hydrofluoric acid 5 inch silicon wafer was immersed in the solution to which 200 ppm was added, and then the surface roughness of the wafer surface when the silicon wafer was immersed in the processing agent for 100 minutes in the number of particles (0.3 μm to 1.0 μm) attached to the wafer surface by the wafer inspection mechanism. The result measured by AMF is shown to Tables 39-44.

However, Table 39 and Table 40 show the results of the characterization of the microfabricated surface treatment agent concentration of 0.5% by weight HF, Tables 41 and 42 likewise 5.0% by weight HF, Tables 43 and 44 are 50% by weight HF. Represents polyoxyethylene.

(Example 2.)

Tables 45 to 48 show the results of measuring the respective properties when diluting the treatment agent added with 2000 ppm of surfactant to 50 wt% hydrofluoric acid to 5.0 wt% and the treatment agent added 2000 ppm to 0.5 wt%.

However, Tables 45 and 46 show the results when the microfabricated surface treatment agent (50.0% by weight HF) was diluted 10-fold and Tables 47 and 48 were diluted 100-fold. POE in these tables represents polyoxyethylene.

1 is a diagram showing the relationship between surfactant concentration and liquid particles.

2 is a diagram showing the relationship between the surfactant concentration and the number of attached particles.

Claims (3)

At least one selected from the group consisting of polyoxyethylene higher alcohol ether, polyoxyethylene oleic acid ester, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether and polyoxyethylene alkylallyl ether in hydrofluoric acid As a material, a fine surface treatment agent prepared by mixing a hydrocarbon-based nonionic surfactant having an HLB value of 7 to 17. 2. The microfabricated surface treatment agent according to claim 1, wherein 10 to 1000 ppm of a hydrocarbon-based nonionic surfactant is contained. The HLB value of a hydrocarbon type nonionic surfactant is 10-15, The micro-processing surface treating agent of Claim 1 characterized by the above-mentioned.