JP2001068444A - Semiconductor substrate processing liquid suppressing adsorption of metal thereto, preparing method for processing liquid, and processing method therefor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress adsorption of metal to a semiconductor substrate surface with no severe concentration adjustment for iron ion, and to suppress adsorption of metal to a substrate surface when processed in a processing liquid. SOLUTION: A semiconductor substrate processing liquid 10 whose main component is an alkaline water solution 11 comprising a potassium hydroxide of pH 8-14, etc., for processing a semiconductor substrate surface 12a is added with iron ion by 0.01-500 ppm for mixture. With an iron hydroxide as a coprecipitation nucleus 14, a metal other than iron is coprecipitated in the form of a metal hydroxide 15. A water solution 13 containing iron ion is the water solution of water-soluble iron salt, and using a steel vessel, liquid bath, or piping, the metal other than iron is coprecipitated in the form of metal hydroxide by utilizing the iron ion eluted from the vessel, etc. The processing method for a semiconductor substrate comprises a process where an alkaline water solution is added with iron ion for mixing by 0.01-500 ppm to provide a processing liquid in which a substrate is submerged for processing, a process for rinsing in a super pure water, a process for washing in an acid solution, and a process for rinsing in a super pure water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing liquid for a semiconductor substrate used in a wet processing step such as a lapping step of a semiconductor substrate represented by a silicon wafer, a chemical etching step, a mechanical chemical polishing step, a cleaning step, and the like. The present invention relates to a method for preparing a processing solution and a method for processing a semiconductor substrate using the same. More specifically, the present invention relates to a processing liquid for a semiconductor substrate such as a chemical etching liquid, a polishing liquid, a cleaning liquid or the like, which suppresses the adsorption of a metal to a semiconductor substrate.

[0002]

2. Description of the Related Art Semiconductor substrates of this kind are treated with various chemicals in the processing process. The chemicals used in this processing are generally "Semiconductor grade"
Grade: SG) or ELectronic grade: E
L) ". However, chemicals for treating semiconductor substrates also contain various metal impurities at a rate of several ppb to several hundred ppb.
For this reason, when treated with such a chemical, the surface of the semiconductor substrate may be contaminated with metal impurities. In particular, when sequentially processing semiconductor substrates of a plurality of lots, the metal impurities adsorbed on the surface of the semiconductor substrate of the previous lot elute into the liquid, and the surface of the semiconductor substrate of the next lot is further contaminated with the metal impurities. It was easy. Conventionally, an alkaline surface treatment liquid for removing contaminant metals from the surface of a semiconductor substrate has been proposed (Japanese Patent Application Laid-Open No. 9-255991). In this surface treatment solution, diethylenetriaminepentaacetic acid is used as a trapping agent for iron ions and zinc ions, triethylenetetraminehexaacetic acid is used as a trapping agent for copper ions and nickel ions, and glutamic acid is used as a trapping agent for aluminum ions. According to this surface treatment liquid, when removing contaminant metals on the substrate surface, the above-mentioned scavenger traps metal ions in the liquid to form a metal complex. Recontamination can be prevented.

[0003]

However, in the above surface treatment liquid, in order for the capturing agent to capture metal ions accurately, it is necessary to adjust the concentration of the capturing agent accurately so as to match the metal ion concentration in the solution. was there. Further, when a plurality of types of metal ions are present in a liquid, there is a catching order for each metal ion, and there is a problem that it is difficult to reliably prevent recontamination of the substrate by the metal ions. An object of the present invention is to provide a processing liquid for a semiconductor substrate capable of suppressing adsorption of a metal to the surface of a semiconductor substrate without requiring strict iron ion concentration adjustment, and a method for preparing the same. Another object of the present invention is to provide a method for treating a semiconductor substrate which can suppress adsorption of metal to the surface of the semiconductor substrate when treated with a treatment liquid.

[0004]

The invention according to claim 1 is
As shown in FIGS. 1A and 1B, in a semiconductor substrate treatment liquid for treating the surface of a semiconductor substrate 12, which contains an alkaline aqueous solution 11 having a pH of 8 to 14 as a main component, iron ions are added to the alkaline aqueous solution 11. 0.01-500ppm
A semiconductor substrate treatment liquid 10 characterized by being added and mixed, in which metal adsorption to a semiconductor substrate is suppressed. In the invention according to claim 1, the pH of the alkaline aqueous solution 11 is 8
~ 14. When the pH is 8 or less, iron hydroxide cannot be formed even when iron ions are added, and thus coprecipitation does not occur. The concentration of iron ions to be added is 0.01 to 500 pp
m. If it is less than 0.01 ppm, the coprecipitation phenomenon does not occur, and if it exceeds 500 ppm, it becomes difficult to remove the iron hydroxide gel in the steps after this treatment step. When the treatment liquid is used as an etching liquid, an iron ion concentration of 0.01 to 500 ppm, preferably 0.1 to 100 ppm is added to and mixed with an alkaline aqueous solution having a pH of 8 to 14. When used as a polishing liquid, an alkaline aqueous solution having a pH of 10 to 12 has an iron ion concentration of 0.1 to 10 ppm, preferably 1 to 5 p.
Add pm and mix. PH 8 when used as a cleaning solution
Iron ion concentration of 0.01 to 13 alkaline aqueous solutions
10 ppm, preferably 0.1 to 1 ppm is added and mixed.

[0005] The invention according to claim 2 is the invention according to claim 1, wherein the alkaline aqueous solution 11 contains potassium hydroxide,
This is a treatment liquid for a semiconductor substrate, which is an aqueous solution of sodium hydroxide, ammonia or tetramethylammonium hydroxide. In the invention according to the second aspect, potassium hydroxide, sodium hydroxide, ammonia or tetramethylammonium hydroxide is suitable for the present invention because it easily generates an iron hydroxide serving as a coprecipitation nucleus. Potassium hydroxide, which has no coordination effect,
Sodium hydroxide is preferred.

As shown in FIGS. 1A and 1B, the invention according to claim 3 is an aqueous solution containing 0.01 to 500 ppm of iron ions in an alkaline aqueous solution 11 having a pH of 8 to 14.
3 and co-precipitation nuclei 14
This is a method for preparing a processing liquid for a semiconductor substrate in which metals other than iron contained in the alkaline aqueous solution 11 are coprecipitated in the form of a metal hydroxide 15. According to the third aspect of the present invention, an iron hydroxide serving as a coprecipitation nucleus is generated in the alkaline aqueous solution 11. Other metal ions dissolved in the aqueous solution 11 co-precipitate in the form of a metal hydroxide 15 using the coprecipitation nucleus 14 as a carrier. As a result, metal ions in the aqueous solution 11 are reduced, and adsorption to the substrate 12 is suppressed.

The invention according to claim 4 is the method according to claim 3, which is a method for preparing a treatment liquid for a semiconductor substrate, wherein the aqueous solution 13 containing iron ions is an aqueous solution of a water-soluble iron salt. In the invention according to claim 4, examples of the aqueous solution of the water-soluble iron salt include iron nitrate, iron citrate, and iron chloride.

According to a fifth aspect of the present invention, an alkaline aqueous solution having a pH of 8 to 14 is brought into contact with a steel container, a liquid tank or a pipe, and iron ions eluted from the container, the liquid tank or the pipe are added to and mixed with the alkaline aqueous solution. The present invention provides a method for preparing a treatment liquid for a semiconductor substrate, wherein a metal other than iron contained in an alkaline aqueous solution is coprecipitated in the form of a metal hydroxide using iron hydroxide as a coprecipitation nucleus. In the invention according to claim 5, iron which is eluted from the surface of the liquid tank or piping parts by contacting the alkaline aqueous solution with a steel liquid tank or pipe parts instead of adding a solution containing iron ions to the alkaline aqueous solution. Using ions, ions of metals other than iron contained in the aqueous solution are reduced. This suppresses metal adsorption to the substrate.

According to a sixth aspect of the present invention, as shown in FIGS. 3 (a) and 3 (b), a semiconductor substrate treatment liquid 10 obtained by adding 0.01 to 500 ppm of iron ions to an alkaline aqueous solution 11 is mixed. This is a semiconductor substrate processing method including a step of immersing and processing the substrate 12 and a step of rinsing the processed semiconductor substrate 12 with ultrapure water 18. The invention according to claim 7 is the invention according to claim 6, wherein the semiconductor substrate is immersed in ultrapure water in a step of rinsing with ultrapure water, and ultrasonic waves are applied in the immersion state to clean the semiconductor substrate. This is a method for processing a semiconductor substrate. The invention according to claim 8 is the invention according to claim 6, wherein the semiconductor substrate 12 is rinsed with the ultrapure water 18 and then washed with the acidic solution 21a as shown in FIGS. 3 (c) and 3 (d). And cleaning the semiconductor substrate 12
Rinsing with ultrapure water 18. In the inventions according to claims 6 and 8, by performing the substrate processing in the above-described step, the adsorption of the impurity metal to the semiconductor substrate 12 can be further suppressed. According to the seventh aspect of the invention, the ultrasonic gel is applied to the rinsing step of the sixth aspect, so that the hydroxide gel on the substrate surface can be easily removed.

[0010]

Embodiments of the present invention will be described in detail with reference to the drawings. The treatment liquid of the present invention is used as a wet treatment liquid for a semiconductor substrate such as a chemical etching liquid, a polishing liquid, and a cleaning liquid. This treatment liquid has an alkaline aqueous solution as a main component and has a function of suppressing adsorption of metal impurities contained in the liquid to the semiconductor substrate. The alkaline aqueous solution includes not only a commercially available chemical solution but also a treated alkaline aqueous solution when processing a plurality of lots of semiconductor substrates. FIG.
As shown in (a), in a commercially available alkaline aqueous solution 11 or an aqueous solution 11 in which a semiconductor substrate has already been processed, metal impurities originally contained in the chemical solution itself or metal impurities eluted from the processed substrate are dissolved. Alternatively, it exists in the form of a hydroxide. As shown in FIG. 1B and FIG. 2, when the semiconductor substrate 12 is immersed in the aqueous solution 11, metal ions as cations are adsorbed on the negatively charged substrate surface 12a. Causes a problem that cannot be easily removed from

The embodiment of the present invention is characterized in that an aqueous solution 13 containing iron ions is added to an alkaline aqueous solution 11 as shown in FIG. As a result, FIG.
As shown in (b), iron ions generate iron hydroxide to form coprecipitated nuclei 14, and the coprecipitated nuclei 14 serve as a carrier, such as Cu (OH) ₂ or Ni (OH) ₂ . Such another metal hydroxide 15 is adsorbed. The coprecipitate 16 consisting of iron hydroxide, which is a coprecipitating nucleus 14, and another metal hydroxide 15, that is, the carrier is δ ⁺
Part and δ ^- part (FIG. 2). When the semiconductor substrate 12 is immersed in the alkaline aqueous solution 11 containing the coprecipitate 16, as shown in FIG.
^{The +} portion and the negatively charged substrate surface 12a attract each other to cause mutual adsorption. However, the mutual adsorption is weaker than the case where the metal ions are directly adsorbed on the substrate surface 12a.
The substrate surface 12a can be easily removed by rinsing with ultrapure water.

In the present embodiment, the semiconductor substrate 12 is cleaned in the steps shown in FIGS. That is, FIG.
As shown by the dashed arrow in (a), the semiconductor substrate treatment liquid 10 obtained by adding an aqueous solution containing iron ions to an alkaline aqueous solution.
The semiconductor substrate 12 is immersed for 1 to 10 minutes in a tank 17 for storing the substrate, and pulled up from the tank 17 as shown by a solid line arrow in FIG. Next, as shown by a dashed arrow in FIG. 3B, the ultrapure water 18 is stored and immersed in a first rinsing tank 19 provided with an ultrasonic device 20 in close contact with the outer bottom surface for 5 to 20 minutes. The surface of the semiconductor substrate 12 is cleaned by applying ultrasonic waves in the immersion state, and is pulled up from the first rinsing bath 19 as shown by a solid line arrow in FIG. Next, as shown by the dashed arrow in FIG. 3 (c), 5 to 10 are stored in the acidic solution tank 21 storing the acidic solution 21a.
Then, the substrate is immersed in the acidic solution tank 21 as shown by a solid line arrow in FIG. Further, as shown by a dashed arrow in FIG. 3 (d), 5 rinsing water is stored in the second rinsing tank 22 storing the ultrapure water 18.
After being immersed for 10 to 10 minutes for cleaning, it is pulled up from the second rinsing bath 22 as shown by a solid arrow in FIG. FIG.
In the step shown in (c), the substrate 12 is
When the metal ions directly adsorbed on the surface of the substrate still exist, the metal ions are removed. Here, as the acidic solution, for example, SC-2 solution composed of hydrochloric acid and hydrogen peroxide solution, or a mixed acid composed of hydrofluoric acid and hydrogen peroxide solution, and the like can be mentioned.

In a process used in another embodiment of the present invention,
Using a steel vessel, liquid tank or piping to elute iron ions from the vessel, etc. without adding an aqueous solution containing iron ions to the treatment liquid, to produce coprecipitation nuclei, that is, iron hydroxide as a carrier Thus, metals other than iron contained in the treatment liquid are coprecipitated in the form of metal hydroxide. This makes it possible to suppress metal adsorption to the substrate surface without adding iron ions to the processing liquid. Note that a steel container or the like means a container or the like made of iron, stainless steel, or another iron-based alloy. In the process used in the above embodiment, the cleaning method using ultrapure water 18
The semiconductor substrate 1 is stored in the first and second rinsing tanks 19 and 22 in which
Although the example in which 2 is immersed is shown, cleaning may be performed by a shower with ultrapure water 18. In this embodiment, an example in which an aqueous solution containing iron ions is added and mixed is described. However, as an element capable of forming a coprecipitation nucleus (carrier) and coprecipitating another metal as a metal hydroxide, Alternatively, aluminum or manganese may be added and mixed with iron.

[0014]

Next, examples of the present invention will be described together with comparative examples. <Example 1> pH 14 containing 40 wt% of potassium hydroxide
Was forcedly contaminated with 100 ppb of copper. Iron nitrate was added to this solution so that the iron ion concentration in the processing solution was 1 ppm, to prepare a processing solution for a semiconductor substrate. A silicon wafer, which was a semiconductor substrate after the normal polishing step, was immersed in a tank containing the above-mentioned processing solution at 50 ° C. for 5 minutes, and pulled up from the processing solution tank. Next, the wafer was immersed in a rinsing bath containing ultrapure water for 5 minutes, and then pulled up from the rinsing bath and dried.

<Embodiment 2> The iron ion concentration in the treatment liquid is 1
Example 1 except that iron nitrate was added at 0 ppm.
A treatment liquid for a semiconductor substrate was prepared in the same manner as in Example 1, and the same silicon wafer as in Example 1 was treated as in Example 1. <Example 3> A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 1 except that iron nitrate was added so that the iron ion concentration in the processing liquid was 100 ppm, and the same silicon wafer as in Example 1 was used. Treated as in Example 1. Example 4 A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 1 except that iron nitrate was added so that the iron ion concentration in the processing liquid was 200 ppm, and the same silicon wafer as in Example 1 was implemented. Treated as in Example 1. <Example 5> A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 1 except that iron nitrate was added so that the iron ion concentration in the processing liquid was 400 ppm, and the same silicon wafer as in Example 1 was used. Treated as in Example 1. Comparative Example 1 A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 1 except that no iron nitrate was added, and the same silicon wafer as in Example 1 was treated as in Example 1.

<Comparative Evaluation 1> The amounts of copper and iron contamination on the surfaces of the silicon wafers treated in Examples 1 to 5 and Comparative Example 1 were measured by total reflection X-ray fluorescence analysis. These results are shown in FIG.
Shown in In Examples 1 to 5, as is apparent from FIG.
It can be seen that the concentration of copper contamination on the wafer surface decreases as the amount of iron ion added increases. When the amount of iron added is in the range of 10 ppm to 100 ppm, the contamination concentration of iron on the wafer surface is reduced, but it is estimated that coprecipitation nuclei of iron hydroxide as a carrier are generated in a large amount in this added range. You. On the other hand, in Comparative Example 1, the wafer surface was more highly contaminated with copper than in Examples 1 to 5.

<Example 6> Commercially available potassium hydroxide was added to 40
Iron nitrate was added to an aqueous solution having a pH of 14 containing wt% so that the concentration of iron ions in the processing solution became 100 ppm, thereby preparing a processing solution for a semiconductor substrate. This commercially available aqueous solution of potassium hydroxide was analyzed with a high-frequency inductively coupled plasma emission spectroscopy-mass spectrometer.
b, 20 ppb nickel and 300 ppb iron. A silicon wafer, which was a semiconductor substrate after the normal polishing step, was immersed in a tank containing the above-mentioned processing solution at 50 ° C. for 5 minutes, and pulled up from the processing solution tank. Next, the silicon wafer was immersed in a first rinsing bath containing ultrapure water for 5 minutes, and then pulled up from the first rinsing bath. Next, this silicon wafer was immersed for 5 minutes in an acidic solution tank storing a 5 wt% hydrofluoric acid aqueous solution, and pulled up from the acidic solution tank. Further, the silicon wafer was immersed in a second rinsing bath containing ultrapure water for 5 minutes, and then pulled up from the second rinsing bath and dried.

<Embodiment 7> The iron ion concentration in the processing solution is 5
A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 6 except that iron nitrate was added so as to be 00 ppm.
The same silicon wafer as above was treated in the same manner as in Example 6. <Example 8> A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 6, except that iron citrate was added so that the iron ion concentration in the processing liquid was 10 ppm. The same treatment as in Example 6 was performed. <Example 9> A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 6, except that iron citrate was added so that the iron ion concentration in the processing liquid was 50 ppm. The same treatment as in Example 6 was performed. <Example 10> The iron ion concentration in the treatment liquid was 100 ppm.
A treatment liquid for a semiconductor substrate was prepared in the same manner as in Example 6 except that iron citrate was added so as to obtain the same silicon wafer as in Example 6. <Example 11> The concentration of iron ions in the treatment liquid was 300 ppm.
A treatment liquid for a semiconductor substrate was prepared in the same manner as in Example 6 except that iron citrate was added so as to obtain the same silicon wafer as in Example 6. <Example 12> The iron ion concentration in the treatment liquid was 100 ppm.
A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 6 except that iron chloride was added so as to obtain the same silicon wafer as in Example 6. Comparative Example 2 A processing liquid for a semiconductor substrate was prepared in the same manner as in Example 6 except that no aqueous solution containing iron ions was added, and the same silicon wafer as in Example 6 was processed as in Example 6.

<Comparative Evaluation 2> Examples 6 to 12 and Comparative Example 2
The amount of copper contamination on the surface of the silicon wafer treated with the above was measured by total reflection X-ray fluorescence analysis. These results are shown in FIG. In Examples 6 to 12, as is clear from FIG.
If the aqueous solution containing iron ions is an aqueous solution that can generate coprecipitated nuclei of iron hydroxide serving as a carrier in an alkaline aqueous solution, the amount of copper contamination on the wafer surface decreases as the amount added increases in any case. I understand. Further, it can be seen that even when impurity metals other than copper are contained in the processing solution, the effect of reducing the concentration of copper contamination on the wafer surface is obtained as in Example 1. In contrast, in Comparative Example 2, the wafer surface was contaminated with copper at a higher concentration than in Examples 6 to 12.

Example 13 Potassium hydroxide was added to 0.00
1000 ppb of iron, 5 ppb of copper, and 5 ppb of nickel were forcibly contaminated in an aqueous solution having a pH of 10.3 containing 4 wt%. This solution has an iron ion concentration of 10 ppm in the processing solution.
Was added to prepare a treatment liquid for a semiconductor substrate. A silicon wafer, which was a semiconductor substrate after the usual polishing process, was immersed in a tank storing the above-mentioned processing solution at 25 ° C. for 5 minutes, and was pulled up from the processing solution tank. Next, the silicon wafer was immersed in a rinsing bath containing ultrapure water for 10 minutes, and then pulled up from the rinsing bath and dried. <Comparative Example 3> Example 13 except that no iron nitrate was added.
A treatment liquid for a semiconductor substrate was prepared in the same manner as in Example 13.
The same silicon wafer as above was treated in the same manner as in Example 13.

<Comparative Evaluation 3> The amount of iron, copper and nickel contamination on the surfaces of the silicon wafers treated in Example 13 and Comparative Example 3 was measured by total reflection X-ray fluorescence analysis. These results are shown in FIG. In Example 13, as is clear from FIG. 6, all contaminant metals including iron as an additive were below the detection limit of total reflection X-ray fluorescence analysis. On the other hand, in Comparative Example 3, it was found that metal impurities were adsorbed on the wafer surface by immersion in the processing solution.

[0022]

As described above, according to the present invention, a processing solution used for a wet etching process such as a chemical etching process, a mechanical chemical polishing process, and a cleaning process for a semiconductor substrate is used for a substrate surface treatment. By using a treatment solution in which iron ions are added to and mixed with an alkaline aqueous solution, iron hydroxide is generated in the alkaline aqueous solution. Since coprecipitation occurs in the form of a hydroxide, adsorption of metal contained in the alkaline aqueous solution to the substrate surface can be suppressed. In particular, in the case of a processing solution using a chelating agent as a scavenger disclosed in Japanese Patent Application Laid-Open No. 9-255991, the concentration of the scavenger must be strictly adjusted in accordance with the concentration of metal ions for which adsorption to the substrate is to be suppressed. The treatment liquid for semiconductor substrates of the present invention has an advantage that it is not necessary to strictly adjust the concentration of iron ions. Also, even if the alkaline aqueous solution contains a plurality of types of metals whose adsorption to the substrate is to be suppressed, the coprecipitation phenomenon of iron hydroxide is used. Metal contamination on the surface of the semiconductor substrate, which is a processed object, can be accurately prevented. As a result, according to the present invention, a processing tank made of high-purity quartz and polytetrafluoroethylene (trade name: Teflon) can be used without using an extremely high-purity expensive alkaline aqueous solution or as a semiconductor substrate processing tank. The use of a steel processing tank makes it possible to prepare a processing liquid for a semiconductor substrate in which metal adsorption to the substrate is suppressed at a relatively low cost. By rinsing the semiconductor substrate treated with the treatment liquid of the present invention with ultrapure water, the coprecipitate adsorbed on the substrate surface can be easily removed, and the metal can be more reliably removed by washing with an acidic solution. can do.

[Brief description of the drawings]

FIG. 1A is a view showing a form of an impurity metal in an aqueous alkaline solution. (B) The figure which shows the coprecipitation phenomenon by the iron hydroxide in the processing liquid for semiconductor substrates.

FIG. 2 is a view showing a behavior of a coprecipitate with respect to a semiconductor substrate in a processing liquid for a semiconductor substrate.

FIG. 3 is a view showing a processing step of the semiconductor substrate according to the embodiment of the present invention;

FIG. 4 is a graph showing the amount of iron ions added and the concentration of copper and iron contaminants on the silicon wafer surface in Examples 1 to 5 and Comparative Example 1.

FIG. 5 is a graph showing the addition amount of a water-soluble iron salt and the concentration of copper contamination on a silicon wafer surface in Examples 6 to 12 and Comparative Example 2.

FIG. 6 is a graph showing the addition of iron ions and the concentration of iron, copper, and nickel contaminants on the silicon wafer surface in Example 13 and Comparative Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Processing liquid for semiconductor substrates 11 Alkaline aqueous solution 12 Semiconductor substrate 13 Aqueous solution containing iron ion 14 Coprecipitation nucleus (carrier) 15 Metal hydroxide 16 Coprecipitate

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsuyoshi Harada 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Inside the Silicon Research Center, Mitsubishi Materials Corporation (72) Ryoko Takada 1-297 Kitabukurocho, Omiya City, Saitama Mitsubishi Silicon Research Center, Materials Co., Ltd. (72) Masafumi Norimoto, Inventor 1-297 Kitabukuro-cho, Omiya City, Saitama F-term (Reference) 5F043 AA01 BB02 BB27 BB30 DD10 DD23 DD30 EE05 EE16 GG10

Claims (8)

[Claims] 1. A treatment liquid for a semiconductor substrate mainly comprising an alkaline aqueous solution (11) having a pH of 8 to 14 for treating the surface of a semiconductor substrate (12), wherein iron ions are added to the alkaline aqueous solution (11). 01-50
A processing liquid for a semiconductor substrate, which is obtained by adding and mixing 0 ppm and suppressing adsorption of a metal to a semiconductor substrate. 2. The treatment liquid for a semiconductor substrate according to claim 1, wherein the alkaline aqueous solution (11) is an aqueous solution of potassium hydroxide, sodium hydroxide, ammonia or tetramethylammonium hydroxide. 3. An alkaline aqueous solution (11) having a pH of 8 to 14 and an aqueous solution (13) containing 0.01 to 500 ppm of iron ions are added and mixed to form an iron hydroxide as a coprecipitation nucleus (14). A method for preparing a treatment liquid for a semiconductor substrate, comprising coprecipitating a metal other than iron contained in (11) in the form of a metal hydroxide (15). 4. The method according to claim 3, wherein the aqueous solution containing iron ions is an aqueous solution of a water-soluble iron salt. 5. An alkaline aqueous solution (11) having a pH of 8 to 14 is brought into contact with a steel container, liquid tank or piping, and iron ions eluted from said container, liquid tank or piping are added to said alkaline aqueous solution (11) and mixed. Thereby, a treatment liquid for semiconductor substrate obtained by coprecipitating metals other than iron contained in the alkaline aqueous solution (11) in the form of a metal hydroxide (15) with iron hydroxide as a coprecipitation nucleus (14). Preparation method. 6. An alkaline aqueous solution (11) containing iron ions in an amount of 0.
Step (a) of immersing the semiconductor substrate (12) in the semiconductor substrate treatment liquid (10) obtained by adding and mixing 01 to 500 ppm to perform treatment.
And a step (b) of rinsing the treated semiconductor substrate (12) with ultrapure water (18). 7. A semiconductor substrate (12) immersed in ultrapure water (18) in a step (b) of rinsing with ultrapure water (18), and applying ultrasonic waves in the immersion state. 7. The method for treating a semiconductor substrate according to claim 6, wherein the cleaning is performed. 8. A step (c) of rinsing the semiconductor substrate (12) with ultrapure water (18) and then washing the semiconductor substrate (12) with an acidic solution (21a), and cleaning the semiconductor substrate (12) with ultrapure water (18). 7. The method for treating a semiconductor substrate according to claim 6, further comprising a step (d) of rinsing in the step (d).