阅读说明：本技术 清洗液、清洗方法和半导体晶片的制造方法 (Cleaning liquid, cleaning method and method for manufacturing semiconductor wafer ) 是由 柴田俊明 河瀬康弘 于 2020-04-07 设计创作，主要内容包括：本发明涉及一种在研磨工序后使用的清洗液,其包含成分(A)：下述通式(1)所表示的化合物；成分(B)：碱性化合物；以及成分(C)：水,表面活性剂的含量为0.001质量％以下。所述通式(1)中,R-(1)、R-(2)各自独立地表示羟基或酚基。(The present invention relates to a cleaning liquid used after a polishing step, which contains a component (a): a compound represented by the following general formula (1); component (B): a basic compound; and component (C): water, and the content of the surfactant is 0.001 mass% or less. In the general formula (1), R 1 、R 2 Each independently represents a hydroxyl group or a phenol group.)

1. A cleaning liquid used after a polishing step, comprising the following components (A) to (C), wherein the content of a surfactant is 0.001% by mass or less,

component (A): a compound represented by the following general formula (1),

component (B): a basic compound, which is a compound selected from the group consisting of,

component (C): the amount of water is controlled by the amount of water,

[ solution 1]

Said general formula(1) In, R₁、R₂Each independently represents a hydroxyl group or a phenol group.

2. A cleaning liquid used after a polishing step, which contains the following components (A) to (C) and substantially no surfactant,

component (A): a compound represented by the following general formula (1),

component (B): a basic compound, which is a compound selected from the group consisting of,

component (C): the amount of water is controlled by the amount of water,

[ solution 2]

In the general formula (1), R₁、R₂Each independently represents a hydroxyl group or a phenol group.

3. The cleaning liquid according to claim 1 or 2, wherein the component (a) comprises ethylenediamine-di-o-hydroxyphenylacetic acid.

4. The cleaning liquid according to any one of claims 1 to 3, wherein the component (B) contains at least one selected from the group consisting of ammonia and quaternary ammonium hydroxide.

5. The cleaning solution of claim 4, wherein the quaternary ammonium hydroxide comprises at least one selected from the group consisting of tetraethylammonium hydroxide, trishydroxyethyl methylammonium hydroxide, tetrabutylammonium hydroxide, triethylmethylammonium hydroxide, diethyldimethylammonium hydroxide, and diethylmethylpropylammonium hydroxide.

6. The cleaning liquid according to any one of claims 1 to 5, wherein the ratio of the mass of the component (A) to the mass of the component (B) is 0.001 to 0.5.

7. The cleaning liquid according to any one of claims 1 to 6, wherein the pH of the cleaning liquid is 9 to 14.

8. The cleaning liquid according to any one of claims 1 to 7, wherein the polishing step is a chemical mechanical polishing step.

9. The cleaning liquid according to any one of claims 1 to 7, wherein the polishing step is a back-polishing step.

10. The cleaning liquid according to any one of claims 1 to 9, wherein the cleaning liquid is used for cleaning a surface on which a compound containing silicon is exposed.

11. A cleaning method comprising a step of cleaning a semiconductor wafer with the cleaning liquid according to any one of claims 1 to 10.

12. A method for producing a semiconductor wafer, comprising a step of cleaning a semiconductor wafer with the cleaning liquid according to any one of claims 1 to 10.

13. The method of manufacturing a semiconductor wafer according to claim 12, further comprising a step of thinning the semiconductor wafer.

Technical Field

The invention relates to a cleaning solution, a cleaning method and a method for manufacturing a semiconductor wafer.

Background

In recent years, in the semiconductor device manufacturing process, along with the high speed and high integration of semiconductor devices, the demand for cleaning the surface of a semiconductor wafer has been becoming more and more severe. In general, cleaning using a cleaning liquid is performed to clean the surface of a semiconductor wafer. In particular, since various contaminants which deteriorate the characteristics of the semiconductor device remain on the surface of the semiconductor wafer after the polishing step, the importance of cleaning the surface of the semiconductor wafer is high.

As a cleaning liquid to be supplied to a cleaning step after a polishing step in a semiconductor device manufacturing process, for example, patent document 1 discloses a cleaning liquid containing a surfactant.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-289060

Disclosure of Invention

Problems to be solved by the invention

In a polishing step represented by a Chemical Mechanical polishing (hereinafter, sometimes simply referred to as "CMP") step and a back-side polishing step, there is a problem that characteristics of a semiconductor device are deteriorated because metal components, polishing particles, and the like remain on a surface of a semiconductor wafer.

However, when the cleaning liquid is an acidic aqueous solution, the abrasive particles represented by colloidal silica are positively charged in the aqueous solution, the surface of the semiconductor wafer is negatively charged, and an electric attraction force acts, and there is a problem that it is difficult to remove the abrasive particles. On the other hand, when the cleaning liquid is an alkaline aqueous solution, since the aqueous solution contains a large amount of hydroxide ions, both the polishing particles represented by colloidal silica and the surface of the semiconductor wafer are negatively charged, and an electrical repulsive force acts, so that the polishing particles are easily removed.

In addition, there is also a possibility that a cleaning liquid containing a surfactant is used for removing the remaining metal components, the abrasive particles, and the like, but the abrasive particles to which the organic compound is attached are coordinated with the surfactant, and there are problems that the organic compound is difficult to dissolve in the cleaning liquid and the abrasive particles are difficult to remove, and there is also a problem that the surfactant itself is likely to remain on the surface of the semiconductor wafer and causes deterioration in the characteristics of the semiconductor device. The cleaning liquid disclosed in patent document 1 contains a surfactant, and therefore has poor particle removability.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning liquid which does not corrode silicon and is excellent in metal removability and fine particle removability. Another object of the present invention is to provide a cleaning method which does not corrode silicon and is excellent in metal removability and particle removability.

Means for solving the problems

As a result of intensive studies, the inventors of the present invention have found that a cleaning liquid containing a combination of components (a) to (C) described later is excellent in metal removability and fine particle removability without corroding silicon.

That is, the gist of the present invention is as follows.

[1] A cleaning liquid used after a polishing step, comprising the following components (A) to (C), wherein the content of a surfactant is 0.001% by mass or less.

Component (A): a compound represented by the following general formula (1)

Component (B): basic compound

Component (C): water (W)

[ solution 1]

In the above general formula (1), R₁、R₂Each independently represents a hydroxyl group or a phenol group.

[2] A cleaning liquid used after a polishing step, comprising the following components (A) to (C) and substantially not containing a surfactant.

Component (A): a compound represented by the following general formula (1)

Component (B): basic compound

Component (C): water (W)

[ solution 2]

In the above general formula (1), R₁、R₂Each independently represents a hydroxyl group or a phenol group.

[3] The cleaning liquid as described in [1] or [2], wherein the above-mentioned component (A) comprises ethylenediamine-di-o-hydroxyphenylacetic acid.

[4] The cleaning solution according to any one of [1] to [3], wherein the component (B) contains at least one selected from the group consisting of ammonia and quaternary ammonium hydroxides.

[5] The cleaning solution according to [4], wherein the quaternary ammonium hydroxide contains at least one selected from the group consisting of tetraethylammonium hydroxide, trishydroxyethyl methylammonium hydroxide, tetrabutylammonium hydroxide, triethylmethylammonium hydroxide, diethyldimethylammonium hydroxide and diethylmethylpropylammonium hydroxide.

[6] The cleaning liquid according to any one of [1] to [5], wherein the ratio of the mass of the component (A) to the mass of the component (B) is 0.001 to 0.5.

[7] The cleaning liquid according to any one of [1] to [6], wherein the pH of the cleaning liquid is 9 to 14.

[8] The cleaning solution according to any one of [1] to [7], wherein the polishing step is a chemical mechanical polishing step.

[9] The cleaning liquid according to any one of [1] to [7], wherein the polishing step is a back polishing step.

[10] The cleaning liquid according to any one of [1] to [9], wherein the cleaning liquid is used for cleaning a surface on which a compound containing silicon is exposed.

[11] A cleaning method comprising a step of cleaning a semiconductor wafer with the cleaning liquid according to any one of [1] to [10 ].

[12] A method for producing a semiconductor wafer, comprising a step of cleaning a semiconductor wafer with the cleaning liquid according to any one of [1] to [10 ].

[13] The method for manufacturing a semiconductor wafer according to [12], further comprising a step of thinning the semiconductor wafer.

ADVANTAGEOUS EFFECTS OF INVENTION

The cleaning liquid and the cleaning method of the present invention do not corrode silicon, and are excellent in metal removability and fine particle removability.

Further, the method for manufacturing a semiconductor wafer of the present invention includes a cleaning step which does not corrode silicon and is excellent in metal removability and particle removability, and therefore, operation failure of a semiconductor device can be suppressed.

Detailed Description

The present invention will be described in detail below, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention. In the present specification, the expression "to" is used in a form including numerical values and physical property values before and after the expression.

(cleaning solution)

The cleaning liquid of the present invention (hereinafter, may be simply referred to as "cleaning liquid") includes a cleaning liquid of embodiment 1 of the present invention and a cleaning liquid of embodiment 2 of the present invention described later.

The cleaning liquid according to embodiment 1 of the present invention contains the following components (a) to (C), and the content of the surfactant is 0.001% by mass or less.

Component (A): a compound represented by the following general formula (1)

Component (B): basic compound

Component (C): water (W)

When the content of the surfactant is 0.001% by mass or less, the polishing particles can be prevented from being coordinated with the surfactant and being difficult to remove in the polishing step. The content of the surfactant is preferably 0.0001% by mass or less, more preferably 0.00001% by mass or less, and further preferably 0% by mass.

The cleaning solution according to embodiment 2 of the present invention contains the components (a) to (C) and substantially no surfactant. The cleaning liquid containing substantially no surfactant means that the content of the surfactant in 100 mass% of the cleaning liquid is 0 mass% to 0.00001 mass%.

When the polishing composition contains substantially no surfactant, the polishing particles can be prevented from being coordinated with the surfactant and being difficult to remove in the polishing step.

The surfactant is a substance having a hydrophilic group and an oleophilic group (hydrophobic group) in the molecule, and examples thereof include alkyl sulfonic acids and salts thereof, alkyl benzene sulfonic acids and salts thereof, alkyl diphenyl ether disulfonic acids and salts thereof, alkyl methyl taurines and salts thereof, sulfosuccinic acid diesters and salts thereof, polyoxyalkylene alkyl ethers and salts thereof, and the like.

(component (A))

The component (A) is a compound represented by the following general formula (1).

[ solution 3]

In the above general formula (1), R₁、R₂Each independently represents a hydroxyl group or a phenol group.

When the cleaning liquid of the present invention contains the component (a), the amino group, the carboxyl group, and the hydroxyl group in the structure of the component (a) coordinate with the metal ion, and capture the metal ion remaining on the surface of the semiconductor wafer to promote dissolution thereof in the cleaning liquid. Therefore, the cleaning liquid of the present invention is excellent in metal removability.

In the above general formula (1), R₁、R₂Each independently is a hydroxyl group or a phenol group, and R is preferably R for the reason of excellent metal removing property of the cleaning solution₁And R₂Both of which are hydroxy, or R₁And R₂Both of which are phenolic groups, more preferably R₁And R₂Both of which are phenolic groups.

The phenol group may include a phenyl group and a hydroxyl group, and one or more hydroxyl groups may be present. The phenyl group may have a substituent other than the hydroxyl group.

Specific examples of the component (A) include ethylenediamine-bis (o-hydroxyphenyl) acetic acid, ethylenediamine-N, N ' -bis [ (2-hydroxy-5-methylphenyl) acetic acid ], ethylenediamine-N, N ' -bis [ (2-hydroxy-5-chlorophenyl) acetic acid ], ethylenediamine-N, N ' -bis [ (2-hydroxy-5-sulfophenyl) acetic acid ], and the like. These components (A) may be used singly or in combination of two or more.

Among these components (a), ethylenediamine-di-o-hydroxyphenylacetic acid and ethylenediamine-N, N' -bis [ (2-hydroxy-5-sulfophenyl) acetic acid ] are preferable, and ethylenediamine-di-o-hydroxyphenylacetic acid is more preferable, because of the excellent particle removability and metal removability of the cleaning liquid.

(component (B))

The component (B) is a basic compound.

When the cleaning liquid of the present invention contains the component (B), the abrasive grains represented by colloidal silica can be negatively charged together with the surface of the semiconductor wafer by making the cleaning liquid contain a large amount of hydroxide ions. Therefore, the electric repulsive force acts, and the cleaning liquid of the present invention is excellent in the fine particle removing property.

Examples of the component (B) include inorganic bases and organic bases. These components (B) may be used singly or in combination of two or more.

Among these components (B), ammonia and quaternary ammonium hydroxide are preferable because of the excellent removal of fine particles from the cleaning liquid, and ammonia, tetraethylammonium hydroxide, triethoxymethylammonium hydroxide, tetrabutylammonium hydroxide, triethylmethylammonium hydroxide, diethyldimethylammonium hydroxide, and diethylmethylpropylammonium hydroxide are more preferable because of the excellent metal removal from the cleaning liquid, and ammonia is particularly preferable because of the excellent removal of iron from the cleaning liquid.

(component (C))

The component (C) is water.

The cleaning liquid of the present invention contains the component (C), and therefore, the cleaning liquid is excellent in metal removability and fine particle removability.

Examples of the water include ion-exchanged water, distilled water, and ultrapure water, and among these, ultrapure water is preferable from the viewpoint of further improving the metal removing property and the fine particle removing property.

The cleaning liquid of the present invention preferably contains no other components than the components (a) to (C), but may contain a trace amount of other components to the extent that the effects of the present invention are not impaired. The content of the other components is preferably 0.001% by mass or less in 100% by mass of the cleaning liquid, and more preferably, the other components are not substantially contained. The cleaning liquid containing substantially no other component means that the content of the other component in 100 mass% of the cleaning liquid is 0 mass% to 0.00001 mass%.

(physical Properties of cleaning solution)

The pH of the cleaning liquid is preferably 9 to 14, more preferably 10 to 13, and further preferably 11 to 12. When the pH is not less than the lower limit, the cleaning liquid is more excellent in the particle removability. When the pH is not more than the upper limit, the degree of freedom in selecting the kind of the component (B) of the cleaning liquid and setting the mixing ratio is high, and the content of the component (B) in the cleaning liquid can be reduced, thereby reducing the raw material cost of the cleaning liquid.

(the ratio by mass of the components of the cleaning liquid)

The ratio of the mass of the component (A) to the mass of the component (B) (mass of the component (A)/mass of the component (B)) is preferably 0.001 to 0.5, more preferably 0.003 to 0.2. When the mass ratio is not less than the lower limit, the metal removability of the cleaning liquid is more excellent. When the mass ratio is not more than the upper limit, the cleaning liquid is more excellent in the fine particle removing property.

(content of each component of the cleaning solution)

The content of the component (a) is preferably 0.0001 to 10% by mass, more preferably 0.0005 to 6% by mass, and still more preferably 0.001 to 1% by mass, based on 100% by mass of the cleaning liquid. When the content of the component (a) is not less than the lower limit, the metal removability of the cleaning liquid is more excellent. When the content of the component (a) is not more than the upper limit, the cleaning liquid is more excellent in the fine particle removing property.

The content of the component (B) is preferably 0.001 to 50% by mass, more preferably 0.005 to 30% by mass, and still more preferably 0.01 to 5% by mass, based on 100% by mass of the cleaning solution. When the content of the component (B) is not less than the lower limit, the cleaning liquid is more excellent in the particle removability. When the content of the component (B) is not more than the upper limit, the pH of the cleaning liquid can be adjusted without impairing the effect of the present invention.

The content of the component (C) is preferably the balance of the components (the component (a) and the component (B)) other than the component (C).

(method for producing cleaning liquid)

The method for producing the cleaning liquid of the present invention is not particularly limited, and the cleaning liquid can be produced by mixing the components (a) to (C).

The order of mixing is not particularly limited, and all the components may be mixed at once, or a part of the components may be mixed in advance, and then the rest of the components may be mixed.

In the method for producing a cleaning liquid of the present invention, the components may be mixed so as to have a content suitable for cleaning, and for the reason that costs for transportation, storage, and the like can be suppressed, a cleaning liquid containing components other than the component (C) at a high content may be prepared and then diluted with the component (C) before cleaning to prepare a cleaning liquid.

The dilution ratio may be set as appropriate depending on the object to be cleaned, and is preferably 20 to 160 times, and more preferably 40 to 120 times.

(cleaning object)

Examples of the cleaning target of the cleaning liquid of the present invention include semiconductor wafers such as semiconductors, glass, metals, ceramics, resins, magnetic materials, and superconductors. Among these cleaning targets, a semiconductor wafer having a surface on which a compound containing silicon is exposed is preferable, and a silicon wafer is more preferable, because metal components and abrasive grains can be removed by cleaning in a short time.

The cleaning liquid of the present invention has excellent particle removability even for a metal surface, and therefore can be suitably used even for a semiconductor wafer having a surface on which a metal or a metal-containing compound is exposed.

Examples of the metal include tungsten, copper, titanium, chromium, cobalt, zirconium, hafnium, molybdenum, ruthenium, gold, platinum, and silver. Examples of the metal-containing compound include a nitride of the metal and a silicide of the metal. Among these metals and metal compounds, tungsten is preferable because of its excellent particle removability of the cleaning liquid.

(types of washing step)

The cleaning liquid of the present invention is used after the polishing step for the reason that it is excellent in the removal of silicon and metal and the removal of fine particles without corroding.

Examples of the polishing step include a Chemical Mechanical Polishing (CMP) step and a back surface polishing step. Among these polishing steps, the CMP step and the back-polishing step are preferable because metal removal and fine particle removal are required after polishing, and the back-polishing step is more preferable because metal removal is more required after polishing.

(CMP Process)

The CMP process is a process of planarizing the surface of a semiconductor wafer by machining the surface. In the CMP process, a special apparatus is generally used to suck the back surface of a semiconductor wafer to a jig called a platen, press the front surface of the semiconductor wafer against a polishing pad, and flow a polishing agent containing polishing particles onto the polishing pad to polish the front surface of the semiconductor wafer.

In CMP, an object to be polished is rubbed against a polishing pad using a polishing agent to polish the object.

The polishing agent includes, for example, colloidal Silica (SiO)₂) Fumed Silica (SiO)₂) Alumina (Al)₂O₃) Cerium oxide (CeO)₂) Etc. abrasive particles. These abrasive particles are a factor of particle contamination of the object to be polished, but the cleaning liquid of the present invention has a function of removing particles adhering to the object to be polished, dispersing them in the cleaning liquid, and preventing them from re-adhering, and therefore exhibits a high effect of removing particle contamination.

The polishing agent may contain additives such as an oxidizing agent and a dispersing agent in addition to the abrasive fine particles.

(Back grinding Process)

The back grinding step is a step of forming a pattern on the surface of a semiconductor wafer so as to enable high-density integration, and then processing the semiconductor wafer to a predetermined thickness. In general, in the back grinding process, the surface of a semiconductor wafer is ground and polished using a diamond grinding wheel.

Since the processing apparatus used in the back grinding step is made of various metals, the surface of the semiconductor wafer is contaminated with various metals. For example, contamination with iron, nickel, or the like from stainless steel parts, and contamination with aluminum, calcium, or the like from semiconductor wafer holders. Since such contamination causes malfunction of the semiconductor device, it is important to perform cleaning with the cleaning liquid of the present invention having excellent metal removability.

(cleaning conditions)

The method of cleaning the cleaning object is preferably a method of bringing the cleaning liquid of the present invention into direct contact with the cleaning object.

Examples of the method for bringing the cleaning liquid of the present invention into direct contact with the cleaning object include: an immersion type in which the cleaning liquid of the present invention is filled in the cleaning tank to impregnate the cleaning object; a rotary type in which the cleaning liquid of the present invention is caused to flow from the nozzle onto the cleaning object and the cleaning object is rotated at a high speed; a spray type cleaning method of spraying the cleaning liquid of the present invention to a cleaning object to clean the cleaning object; and so on. Among these methods, a rotary type and a spray type are preferable because contamination can be removed more efficiently in a short time.

Examples of the apparatus for performing such cleaning include a batch-type cleaning apparatus that simultaneously cleans a plurality of cleaning objects stored in a cassette, and a single-wafer-type cleaning apparatus that cleans 1 cleaning object by being attached to a supporting frame. Among these apparatuses, a single-wafer type cleaning apparatus is preferable because the cleaning time can be shortened and the use of the cleaning liquid of the present invention can be reduced.

The method of cleaning the object to be cleaned is preferably a cleaning method using physical force, more preferably brushing using a cleaning brush or ultrasonic cleaning at a frequency of 0.5 mhz or more, and further preferably brushing using a resin brush for the reason of being more suitable for cleaning after the CMP step or the back grinding step, for the reason of further improving the removability of particles adhering to the object to be cleaned and enabling the cleaning time to be shortened.

The material of the resin brush is not particularly limited, and polyvinyl alcohol and polyvinyl formal are preferable for the reason of easy production of the resin brush itself.

The cleaning temperature may be 20 to 30 ℃ or 30 to 70 ℃ within a range not impairing the performance of the semiconductor wafer.

(cleaning method)

The cleaning method of the present invention is a method including a step of cleaning a semiconductor wafer using the cleaning liquid of the present invention, and is as described above.

(method for manufacturing semiconductor wafer)

The method for manufacturing a semiconductor wafer of the present invention includes the step of cleaning a semiconductor wafer with the cleaning liquid of the present invention, and is as described above.

The method for manufacturing a semiconductor wafer of the present invention preferably further comprises a step of thinning the semiconductor wafer. The step of thinning the semiconductor wafer may be the back grinding step described above, and in this step, the semiconductor wafer is preferably thinned to a thickness of 100 μm or less.

Examples

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the description of the examples below, as long as the gist thereof is not deviated.

(raw materials)

Component (A-1): ethylenediamine bis (o-hydroxyphenyl) acetic acid (manufactured by Tokyo chemical industry Co., Ltd.)

Component (A' -1): ethylenediaminetetraacetic acid (Fuji film and pure drug industry)

Component (B-1): ammonia (manufactured by Tokyo chemical industry Co., Ltd.)

Component (B-2): tetraethylammonium hydroxide (manufactured by Tokyo chemical industry Co., Ltd.)

Component (X-1): polyoxyethylene lauryl ether (manufactured by Tokyo chemical industry Co., Ltd.)

Component (X-2): sodium dodecylbenzenesulfonate (manufactured by Tokyo chemical industry Co., Ltd.)

Component (C-1): water (W)

(measurement of pH)

The cleaning solutions obtained in examples and comparative examples were stirred in a thermostatic bath at 25 ℃ with a magnetic stirrer, and the pH was measured with a pH meter (model name "D-24", manufactured by horiba, Ltd.).

(measurement of corrosivity)

A silicon substrate (manufactured by ADVANTEC, Inc.) on which silicon dioxide was evaporated in a film thickness of 0.3 μm was cut into 20mm squares, and the substrate was immersed in 20mL of the cleaning solution obtained in examples and comparative examples at 25 ℃ for 4 hours. Thereafter, the substrate was taken out, and the thickness of the substrate after immersion was measured by an optical interference film thickness measuring apparatus (model name "VM-1020S", manufactured by SCREEN Semiconductor Solutions). The elution rate of silica eluted in 4 hours was calculated from the thickness of the substrate measured (Per minute), the corrosiveness was evaluated.

(measurement of Metal-removing ability)

To the cleaning liquids obtained in examples and comparative examples, an "ICP multielement standard solution IV" (product name, 23 element dilute nitric acid solution manufactured by Merck) was added so that the concentration of each metal was 1 ppb. The obtained cleaning liquid containing a trace amount of metal was supplied at 1.2L/min while applying ultrasonic waves to the surface of a silicon substrate (manufactured by ADVANTEC corporation) at 40 ℃ for 1 minute, and the silicon substrate was cleaned with ultrapure water for 1 minute and spin-dried to obtain a silicon substrate for test. The residue on the surface of the silicon substrate for the test was recovered with an aqueous solution containing 0.1 mass% hydrofluoric acid and 1 mass% nitric acid, and the amount of metal (aluminum, iron, zinc, and lead) was measured by an inductively coupled plasma mass spectrometer (model name "ELEMENT 2", manufactured by Thermo Fisher Scientific Co., Ltd., ICP-MS)The concentration of the metal remaining on the surface of the test silicon substrate (atoms/cm) was measured and calculated²) The metal removability was evaluated.

(measurement of Fine particle-removing Property)

100mL of a slurry of colloidal silica (trade name "PL-3", manufactured by Hibiscus chemical Co., Ltd.) was supplied onto a silicon substrate (manufactured by ADVANTEC, Ltd.) having a diameter of 8 inches, and spin-dried using a multifunctional spin coater (model name "KSSP-201", manufactured by Kaijo, Ltd.). Then, it was confirmed that a predetermined number of silica particles having a size of 0.06 μm or more were adhered to the surface of the silicon substrate by using a laser surface inspection apparatus (model name "LS-6600", manufactured by Hitachi height, Ltd.). The cleaning liquids obtained in examples and comparative examples were supplied to the surface of the silicon substrate to which the silica particles had adhered, and the silicon substrate was subjected to ultrasonic cleaning at 23 ℃ for 1 minute using a multifunctional spin coater to remove the silica particles adhered to the surface of the silicon substrate. Thereafter, the silicon substrate was cleaned with ultrapure water for 1 minute and spin-dried to obtain a silicon substrate for test. The number of silica particles (defect number) having a particle diameter of 0.06 μm or more on the surface of the obtained test silicon substrate was measured by using a laser surface inspection apparatus, and the particle removability was evaluated.

[ example 1]

The cleaning solution was obtained by mixing each component (A-1) in an amount of 0.0015% by mass, the component (B-1) in an amount of 0.3500% by mass and the balance (C-1) in 100% by mass of the cleaning solution.

The evaluation results of the obtained cleaning liquid are shown in table 1.

Examples 2 to 4 and comparative examples 1 to 6

A cleaning solution was obtained in the same manner as in example 1, except that the kinds and contents of the raw materials were as shown in table 1.

The evaluation results of the obtained cleaning liquid are shown in table 1.

In comparative example 6, since the component (A-1) was insoluble in the component (C-1), evaluation could not be performed.

As is clear from Table 1, the cleaning liquids obtained in examples 1 to 4 did not corrode silicon, and were excellent in metal removability and fine particle removability.

On the other hand, the cleaning liquids obtained in comparative examples 2 to 4 containing a surfactant did not corrode silicon and were excellent in metal removal property, but were poor in particle removal property. In addition, the cleaning liquids obtained in comparative examples 1 and 5, which did not contain the component (a), did not corrode silicon and were excellent in the removal of fine particles, but were poor in the metal removal property. In comparative example 6 containing no component (B), the component (A-1) was not dissolved in the component (C-1), and therefore, evaluation could not be performed.

Although the present invention has been described in detail with reference to the specific embodiments, it is a matter of course that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention. The present application is based on the japanese patent application filed on 15/4/2019 (japanese patent application 2019-076762), the content of which is incorporated in the present specification by reference.

Industrial applicability

The cleaning liquid of the present invention does not corrode silicon and is excellent in metal removability and particle removability, and therefore can be suitably used after a polishing step, particularly after a CMP step or a back-side polishing step.