TW202007737A - Treatment solution and treatment method - Google Patents

Abstract

The purpose of the present invention is to provide a processing solution and a processing method which, when applied to a laminate body including an InP layer and an SiO2 layer formed on the InP layer, enables selectively removing the SiO2 layer and can suppress defects in the SiO2 layer and surface roughness of the InP layer. The invention is of a processing method and a processing solution which contains hydrogen fluoride and an anti-corrosive agent, wherein the number of coarse particles with a particle size greater than or equal to 0.10 [mu]m per 1 mL of the processing solution is less than 100 particles/mL, the number of coarse particles with a particle size greater than or equal to 0.05 [mu]m per 1 mL of the processing solution is less than 500 particles/mL, and the value of the ratio of the number of coarse particles with a particle size greater than or equal to 0.10 [mu]m per 1 mL of the processing solution to the number of coarse particles with a particle size greater than or equal to 0.05 [mu]m per 1 mL of the processing solution is greater than 0.010 and less than 1.000.

Description

Treatment liquid and treatment method

The invention relates to a processing liquid and a processing method.

In recent years, image sensors (infrared sensors) with sensitivity in the infrared region have been commercialized. In the light-receiving element used for the infrared sensor, for example, a photoelectric conversion layer including a group III-V semiconductor such as InGaAs (indium gallium arsenide) is used. In the photoelectric conversion layer, charges are generated by absorbing infrared rays (photoelectricity is performed) Conversion). Various proposals have been made regarding the element structure of such a light-receiving element or imaging element.

For example, Patent Literature 1 describes a light-receiving element including a plurality of photoelectric conversion layers containing compound semiconductors and absorbing wavelengths in the infrared region to generate electric charges, and insulating films formed by surrounding the plurality of photoelectric conversion layers respectively (Patent Application No. 1 item). [Advanced technical literature] [Patent Literature]

[Patent Literature 1] International Publication No. 2017/122537

When manufacturing the light-receiving element described in Patent Document 1, an etching process for an SiO ₂ layer having a laminate of an InP layer and an SiO ₂ layer formed on the InP layer is required.

Therefore, an object of the present invention is to provide a layered body having an InP layer and an SiO ₂ layer formed on the InP layer that can selectively remove SiO ₂ and can suppress defects of the SiO ₂ and surface roughness of the InP layer Degree of treatment fluid and treatment method.

The inventors conducted intensive investigations to solve the above-mentioned problems, and as a result, they learned that the predetermined processing liquid can selectively remove SiO ₂ when applied to a laminate having an InP layer and a SiO ₂ layer formed on the InP layer. The invention can be completed by suppressing the defects of SiO ₂ and the surface roughness of the InP layer.

That is, the present invention is the following [1] to [18]. [1] A processing liquid containing hydrogen fluoride and a resist, the number of coarse particles with a particle size of 0.10 μm or more per 1 mL of the processing liquid is less than 100 particles/mL, and the particle size of the processing liquid is 0.05 per 1 mL The number of coarse particles above μm is less than 500 particles/mL, and the number of coarse particles with a particle size of 0.10 μm or more per 1 mL of the treatment liquid and the coarse particles with a particle size of 0.05 μm or more per 1 mL of the treatment liquid The ratio of the number of is greater than 0.010 and less than 1.000. [2] The treatment liquid according to [1], wherein the treatment liquid further contains ammonium fluoride. [3] The treatment liquid according to [1] or [2], wherein the content of fluorine atoms is in the range of 0.01% by mass to 15% by mass relative to the total mass of the treatment liquid. [4] The treatment liquid according to any one of [1] to [3], further comprising at least one selected from the group consisting of metal ions having a standard electrode potential greater than 0 V and an oxidizing agent, the metal ions And the total content of the oxidizing agent is 10 mass ppb or less with respect to the total mass of the treatment liquid. [5] The treatment liquid according to [4], wherein the value of the ratio of the content of fluorine atoms to the total content of the metal ion and the oxidant is in the range of 20,000 to 10,000,000. [6] The treatment liquid according to [4] or [5], wherein the value of the ratio of the content of the resist to the content of the metal ions and the oxidant is in the range of 40000 to 5000000. [7] The treatment liquid according to any one of [1] to [6], whose pH is in the range of 1 to 5. [8] The processing liquid according to any one of [1] to [7], wherein the resist contains a compound selected from the group consisting of a mercapto group, an azole derivative, a thiazole derivative, a hydroxycarboxylic acid, and a reducing agent And at least one of the group consisting of sugars. [9] The processing liquid according to any one of [1] to [8], wherein the resist contains a mercaptan selected from 2-mercaptopyridine, mercaptosuccinic acid, 2-aminoethanethiol, bismuth mercaptan , 2-mercaptobenzimidazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto-1,2,4-triazole, 5-mercapto-1H -Tetrazole, 2-aminobenzimidazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, tetrazole, 5-amino At least one of the group consisting of tetrazole, citric acid, gluconic acid, DL-tartaric acid, galactaric acid, oxalic acid, diethylhydroxylamine, ascorbic acid, fructose, glucose and ribose. [10] The treatment liquid according to any one of [1] to [9], wherein the content of the resist is within a range of 0.01% by mass to 1.0% by mass relative to the total mass of the treatment liquid. [11] The treatment liquid according to any one of [1] to [10], wherein the value of the ratio of the content of fluorine atoms to the content of the resist is in the range of 0.01 to 50. [12] The treatment liquid according to any one of [1] to [11], whose conductivity is in the range of 200 mS/cm to 1200 mS/cm. [13] The treatment liquid according to any one of [1] to [12], which further contains a non-fluorine-based non-ionic surfactant. [14] The treatment liquid according to [13], wherein the non-fluorine-based nonionic surfactant contains a polyoxyethylene lauryl ether, polyoxyethylene polyoxypropylene glycol, lauryl glucoside, and octylphenol At least one of the group consisting of ethoxylates. [15] The treatment liquid according to [13] or [14], wherein the content of the non-fluorine-based nonionic surfactant is within a range of 1 mass ppm to 0.5 mass% relative to the total mass of the treatment liquid. [16] A treatment method for the treatment liquid according to any one of [1] to [14]. [17] A method for processing, which is selectively removed with containing InP layer In _x P sum is formed on the InP layers comprising SiO SiO SiO ₂ of ₂ layers laminate of _two layers and comprising the [1] The step of contacting the treatment liquid described in any one of [15] with the laminate. Here, x is a real number greater than 0 and less than 1. [18] A processing method that selectively removes an InP layer containing In _x P and a coating layer formed on the InP layer, a part of the region of the coating layer is formed of an SiO ₂ layer, and other regions are made of In _z Ga _(1-z) The SiO ₂ layer of the laminate formed of the InGaAs layer of As, and includes a contacting step of bringing the treatment liquid described in any one of [1] to [15] into contact with the laminate. Among them, x and z are independently real numbers greater than 0 and 1 or less. [Effect of the invention]

According to the present invention, it is possible to provide a treatment capable of selectively removing SiO ₂ and suppressing the defects of SiO ₂ and the surface roughness of the InP layer when applied to a laminate having an InP layer and an SiO ₂ layer formed on the InP layer Liquid and processing methods.

Furthermore, according to the present invention, it is possible to provide an InP layer containing In _x P and a coating layer formed on the InP layer, a part of the region of the coating layer is formed of the SiO ₂ layer, and other regions are made of In _z Ga _{( 1-z)} A processing liquid and a processing method capable of selectively removing SiO ₂ and suppressing the defects of SiO ₂ and the surface roughness of the InP layer when the laminated body is formed of an InGaAs layer of As.

In the present invention, the range indicated by "~" is considered to include both sides of "~" within the range. For example, "A to B" is considered to include "A" and "B" within its scope. In addition, 1 Å means 0.1 nm.

[Treatment liquid] The treatment liquid of the present invention will be described in detail. The treatment liquid of the present invention contains hydrogen fluoride and a resist.

<Coarse particles> In addition, in the processing liquid of the present invention, the number of coarse particles with a particle size of 0.10 μm or more per 1 mL of the processing liquid is defined as A [pieces/mL], and the coarse particles with a particle size of 0.05 μm or more per 1 mL of the processing liquid are used. The number of particles is set to B [particles/mL], and simultaneously satisfies the relationship represented by the following formulas (1) to (3). That is, the number of coarse particles with a particle size of 0.10 μm or more per 1 mL of the processing solution is less than 100 particles/mL, and the number of coarse particles with a particle size of 0.05 μm or more per 1 mL of the processing solution is less than 500 particles/mL. The value of the ratio of the number of coarse particles with a particle size of 0.10 μm or more per 1 mL of the processing liquid to the number of coarse particles with a particle size of 0.05 μm or more per 1 mL of the processing liquid is greater than 0.010 and less than 1.000. A＜100 (1) B＜500 (2) 0.010＜A/B＜1.000 (3)

In the present invention, A and B must satisfy the above relationship. If the relationship is not satisfied, the performance of the treatment liquid will be adversely affected.

If A ≥ 100 [pieces/mL], coarse particles with a particle size of 0.10 μm or more tend to remain on the object to be processed (for example, a semiconductor substrate), thereby increasing the residue. In addition, the number of SiO ₂ defects increases.

If B ≥ 500 [pieces/mL], coarse particles with a particle diameter of 0.05 μm or more are adsorbed on the object to be processed (for example, a semiconductor substrate), thereby making the surface roughness of the substrate surface after etching (the surface roughness of the InP layer) Degrees).

The number of coarse particles A and B are not just simple, A/B (the number of coarse particles with a particle size of 0.10 μm or more per 1 mL of processing solution and the particle size of 0.05 μm or more per 1 mL of processing solution) The ratio of the number of coarse particles) needs to satisfy 0.010<A/B<1.000. If this relationship is not satisfied, the defects of SiO ₂ and the surface roughness of the InP layer will increase.

Here, the number of coarse particles in the treatment liquid is the number of particles having a particle size of 0.10 μm or more or a particle size of 0.05 μm or more measured using a liquid in-particle counter (KS-18F, manufactured by RION Co., Ltd.) ( /ML).

The ratio A/B of the ratio A/B of the number of coarse particles with a particle size of 0.1 μm or more per 1 mL of the processing liquid to the number of coarse particles with a particle size of 0.05 μm or more per 1 mL of the processing liquid is usually 0.01 to 0.80, It is preferably 0.05 to 0.80, more preferably 0.08 to 0.50, and even more preferably 0.10 to 0.30. The number A of coarse particles with a particle size of 0.10 μm or more per 1 mL of the processing liquid is preferably 1/mL or more and less than 100/mL, preferably 1/mL to 80/mL is 1/mL to 50/mL is more preferable. The number B of coarse particles with a particle diameter of 0.05 μm or more per 1 mL of the processing liquid is preferably 1 particle/mL or more and less than 500 particles/mL, preferably 1 particle/mL to 300 particles/mL, more preferably, 3/mL to 200/mL is more preferable.

<Fluorine source> ＜＜hydrogen fluoride＞＞ In the treatment liquid of the present invention, hydrogen fluoride may exist as molecular hydrogen fluoride, or it may be ionized to dissociate into hydrogen ions and fluoride ions. The hydrogen fluoride used in the production of the treatment liquid of the present invention is not particularly limited, but from the viewpoint of ease of treatment, it is preferable to use hydrofluoric acid as an aqueous solution. In addition, in the present invention, fluorine may be in any form as long as it is a fluorine atom, and includes fluoride ion, fluorine in the molecule, and fluorine in the ion.

＜＜Ammonium fluoride＞＞ The treatment liquid of the present invention may further contain ammonium fluoride.

<<Other fluorine source>> The treatment liquid of the present invention may contain a fluorine source other than the above-mentioned hydrogen fluoride and ammonium fluoride as the fluorine source. Examples of such a fluorine source include hexafluorosilicic acid (H ₂ SiF ₆ ), tetrafluoroboric acid (HBF ₄ ), sodium fluoride (NaF), and potassium fluoride (KF).

<Content of Fluorine Atoms> The content of fluorine atoms in the treatment liquid of the present invention is not particularly limited, but it is usually in the range of 0.001 to 20% by mass relative to the total mass of the treatment liquid. Among them, the range of 0.01% by mass to 15% by mass is preferred, the range of 0.03% by mass to 10% by mass is more preferred, and the range of 0.05% by mass to 3% by mass is even more preferred. If the content of fluorine atoms in the treatment liquid is within this range, the defects of SiO ₂ will be further reduced.

<<Measurement method/measurement condition of fluorine atom content>> The content of fluorine atoms in the treatment liquid of the present invention is determined by measuring fluoride ions by ion chromatography. The measurement range of the fluoride ion content measured by ion chromatography is usually several mass ppm to several tens of mass ppm, so when measuring a sample solution with a fluoride ion content of several mass %, it is appropriately diluted The magnification (usually 10 to 10000 times) is used to dilute the sample solution for measurement, and the value obtained by multiplying the measured value by the dilution magnification is used as the content of fluoride ion in the sample solution. When the content of the fluoride ion in the sample solution is not known at all, the dilution rate is set to 1000 times to measure, when the content of fluoride ion in the diluted sample solution enters the measurement range (number of mass ppm ~ Tens of mass ppm), multiply the measured value by the dilution ratio to be the fluoride ion content in the sample solution before dilution. When the measurement range is not entered, change the dilution ratio and repeat the measurement until the measured value enters the measurement range.

The measurement conditions of fluoride ions measured by ion chromatography are shown below. Use column: ion exchange resin (inner diameter 4.0 mm, length 25 cm) Mobile phase: sodium bicarbonate solution (1.7 mmol/L)-sodium carbonate solution (1.8 mmol/L) Flow rate: 1.5 mL/min Sample injection volume: 25 μL Column temperature: 40℃ Suppressor: electrodialysis type Detector: conductivity detector (30℃)

<Resist> The above resist is preferably a resist for the InP (indium phosphorous) layer and the InGaAs (indium gallium arsenide) layer. The etching of fluorine on the SiO ₂ layer generates hexafluorosilicic acid (H ₂ SiF ₆₎ by utilizing the high nucleophilicity of fluoride ions to form strong bonds with silicon atoms and the interaction of protonation to the silicic acid skeleton and react with SiO ₂ nH ₂ O), and corrode it. The resist is adsorbed on the InP layer and the InGaAs layer to protect them from the attack of fluoride ions, whereby the elution of these is suppressed, thereby protecting the InP layer and the InGaAs layer from being etched by the etching treatment liquid.

<<Types of resist>> It is preferable that the resist contains at least one selected from the group consisting of a compound having a mercapto group, an azole derivative, a thiazole derivative, a hydroxycarboxylic acid, a reducing agent, and a saccharide.

Examples of the compound having the aforementioned mercapto group include 2-mercaptopyridine, mercaptosuccinic acid, 2-aminoethanethiol, bismuththiol, 2-mercaptobenzimidazole, 2-amino-5-mercapto-1, 3,4-thiadiazole, 3-amino-5-mercapto-1,2,4-triazole and 5-mercapto-1H-tetrazole.

Examples of the acrazole derivatives include 2-aminobenzimidazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, Tetrazole and 5-aminotetrazole.

Examples of the thiazole derivatives include 2-aminothiazole.

Examples of the hydroxycarboxylic acid include citric acid, gluconic acid, DL-tartaric acid, and galactaric acid.

Examples of the reducing agent include oxalic acid, diethylhydroxylamine, and ascorbic acid.

Examples of the sugars include fructose, glucose, and ribose.

<Content of resist> In the processing liquid of the present invention, the content of the resist is not particularly limited, but it is usually 0.005 mass% to 2.0 mass% relative to the total mass of the processing liquid. Among them, the range of 0.01% by mass to 1.0% by mass is preferred, 0.01% by mass to 0.8% by mass is more preferred, 0.01% by mass to 0.5% by mass is further preferred, and 0.05% by mass to 0.5% by mass It is even better. In the treatment liquid of the present invention, if the content of the resist is within this range, the surface roughness of the InP layer and defects of SiO ₂ can be suppressed to a higher level.

(Measurement method/measurement condition of resist content) The content of the resist in the treatment liquid of the present invention can be measured by gas chromatography-mass spectrometry (GC/MS) method.

The measurement conditions of the resist content measured by the GC/MS method are shown below. Gas chromatography mass analysis device: GCMS-2020 (manufactured by Shimadzu Corporation) Capillary column: InertCap 5MS/NP 0.25 mmI.D.×30 m df=0.25 μm Sample introduction method: shunt 75 kPa constant pressure Gasification chamber temperature: 250℃ Column oven temperature: 80℃(2 min)-500℃(13 min) heating rate 15℃/min Carrier gas: Helium Separator purge flow: 5 mL/min Split ratio: 25:1 Interface temperature: 250℃ Ion source temperature: 200℃ Measurement mode: Scan m/z=85～500 Sample introduction volume: 1 μL The resist is classified from the obtained measurement results, and compared with the sample to find the content.

<Content Ratio of Fluorine to Resist> In the treatment liquid of the present invention, the ratio of the content of the fluorine atom (set to X [mass %]) to the content of the resist (set to Y [mass %]) The value (X/Y) is not particularly limited, but it is preferably 0.01 to 50, more preferably 0.01 to 30, even more preferably 0.01 to 20, and still more preferably 0.01 to 10. In the treatment liquid of the present invention, if X/Y is within this range, the value of SiO ₂ ER (etching rate of SiO ₂ layer)/InP ER (etching rate of InP layer) will further increase, and the SiO ₂ selectivity will Further improve.

<Metal ion/oxidant> The treatment liquid of the present invention may further contain at least one selected from the group consisting of metal ions having a standard electrode potential greater than 0 V and an oxidizing agent (hereinafter sometimes referred to as "oxidizing agent, etc."). When the processing liquid of the present invention further contains an oxidizing agent or the like, the total content of the oxidizing agent and the like is preferably 10 mass ppb or less with respect to the total mass of the processing liquid, and it is more undetected. When no oxidizing agent or the like is detected, it can be regarded that the treatment liquid does not substantially contain an oxidizing agent or the like, and the content of the oxidizing agent or the like can be regarded as 0 mass ppt. In the treatment liquid of the present invention, if at least one content selected from the group consisting of an oxidant and a metal ion with a standard electrode potential greater than 0 V is within this range, the surface roughness of the InP layer and InGaAs layer can be further suppressed .

＜<Metal ion with standard electrode potential greater than 0V＞> Standard electrode potential is the electrode potential for a standard state of an electrochemical reaction (electrode reaction) (when the activity of all chemical species participating in the reaction is 1 and becomes an equilibrium state), it is It is expressed based on the potential of a standard hydrogen electrode (0 V). Examples of metal ions with a standard electrode potential greater than 0 V are bismuth ions (Bi ³⁺ , 0.3172 V), copper ions (Cu ²⁺ , 0.340 V), mercury ions (Hg ₂ ²⁺ , 0.796 V), and silver ions (Ag ⁺ , 0.7991 V), palladium ion (Pd ²⁺ , 0.915 V), iridium ion (Ir ³⁺ , 1.156 V), platinum ion (Pt ²⁺ , 1.188 V) and gold ion (Au ³⁺ , 1.52 V), But it is not limited to these.

(Measurement method/measurement condition of metal ion content) The content of metal ions with a standard electrode potential greater than 0 V in the treatment solution of the present invention can be measured by ICP/MS (Inductively Coupled Plasma/Quality Analysis) method.

The measurement conditions of the metal ion content measured by the ICP/MS method are shown below. ICP-MS analysis device: Agilent8800 (manufactured by Agilent) RF output (W): 600 Carrier gas flow (L/min): 0.7 Supplementary gas flow (L/min): 1 Sampling position (mm): 18

＜＜oxidant＞＞ In the present invention, the oxidant means a compound capable of corroding the InP layer or InGaAs layer and dissolving it in the treatment liquid. Examples of the oxidizing agent are nitric acid, hydrogen peroxide, and periodic acid, but these are not limited.

The content of the oxidizing agent in the case where the treatment liquid of the present invention contains an oxidizing agent is not particularly limited, but it is preferably 0.5 mass ppb or less with respect to the total mass of the treatment liquid, and is not detected (0 mass% is preferable).

(Measurement method/measurement condition of oxidant content) Furthermore, the content of the oxidizing agent in the treatment liquid of the present invention can be measured by a measuring method corresponding to the type of oxidizing agent such as ion chromatography, high-speed liquid chromatography, spectrophotometer, microenzyme immunoanalyzer, or titration.

((Measurement method/measurement condition of nitric acid content)) The content of nitric acid in the treatment liquid of the present invention is determined by measuring the nitric acid ion as an anion component by ion chromatography. The measurement range of the content of nitrate ions measured by ion chromatography is usually several mass ppm to several tens of mass ppm. Therefore, when measuring a sample solution with a content of nitrate ions of several mass %, use an appropriate dilution ratio ( Usually 10 to 10000 times) Dilute the sample solution for measurement, and multiply the measured value by the dilution rate as the content of nitrate ion in the sample solution. When the content of nitrate ions in the sample solution is not known at all, the dilution rate is set to 1000 times and measurement is performed. When the content of nitrate ions in the diluted sample solution enters the measurement range (numerous mass ppm to tens of Mass ppm), the measured value is multiplied by the dilution ratio as the content of nitrate ions in the sample solution before dilution. When the measurement range is not entered, the dilution ratio is changed and measurement is repeated until the measured value enters the measurement range.

The measurement conditions of nitrate ions measured by ion chromatography are shown below. Use column: ion exchange resin (inner diameter 4.0 mm, length 25 cm) Mobile phase: sodium bicarbonate solution (1.7 mmol/L)-sodium carbonate solution (1.8 mmol/L) Flow rate: 1.5 mL/min Sample injection volume: 25μL Column temperature: 40℃ Suppressor: electrodialysis type Detector: conductivity detector (30℃)

((Measurement method/measurement condition of hydrogen peroxide content)) The content of hydrogen peroxide in the treatment liquid of the present invention was measured using a Hiranuma hydrogen peroxide counter (HP-300, manufactured by Hitachi High-Tech Science Corporation). In general, the general measurement concentration range is from several mass ppm to several tens of mass ppm. Therefore, when measuring several mass% of the sample, it is diluted to an appropriate range (10 to 10,000 times) for measurement. Multiply the measured value by the dilution ratio, and use the value as the concentration of the actual treatment solution. Without knowing the concentration, concentrate to 1000 times for measurement, and use the value when the peak value is between several mass ppm and several tens of mass ppm. If there is no entry, change the dilution ratio and optimize it to obtain the concentration.

<Content ratio of fluorine to oxidant etc.> In the treatment liquid of the present invention, the content of the fluorine atom (X [mass %]) and the total content of metal ions and oxidant (C+D) of the standard electrode potential greater than 0 V The value of [mass %]) ratio [X/(C+D)] is not particularly limited, but it is usually in the range of 300 to 30000000. Among them, it is preferably in the range of 20,000 to 10,000,000, more preferably in the range of 30,000 to 8000000, and still more preferably in the range of 50,000 to 5000000. Among them, the content of fluorine atoms is set to X [mass %], the content of oxidizing agent is set to C [mass %], and the content of metal ions with a standard electrode potential greater than 0 V is set to D [mass %]. In the treatment liquid of the present invention, if X/(C+D) is within this range, the surface roughness of the InP layer can be further suppressed and the defects of SiO ₂ can be further suppressed.

＜<Content ratio of resist to oxidant etc.＞＞ Furthermore, in the treatment liquid of the present invention, the ratio of the content of the resist (Y [mass %]) to the total content of the metal ion and oxidizer (C+D [mass %]) of the standard electrode potential greater than 0 V The value [Y/(C+D)] is not particularly limited, but it is usually in the range of 5,000 to 6,500,000. Among them, it is preferably in the range of 40000 to 5000000, more preferably 40000 to 3000000, and even more preferably 50000 to 1000000. Among them, the content of the resist is Y [mass %], the content of the oxidant is C [mass %], and the content of metal ions with a standard electrode potential greater than 0 V is D [mass %]. In the treatment liquid of the present invention, if Y/(C+D) is within this range, the surface roughness of the InP layer and the surface roughness of the InGaAs layer are further suppressed.

<Non-fluorinated non-ionic surfactant> The treatment liquid of the present invention may further contain a non-fluorine-based non-ionic surfactant.

＜＜Types of non-fluorine-based non-ionic surfactants＞＞ Examples of the non-fluorine-based nonionic surfactant are polyoxyethylene lauryl ether, polyoxyethylene polyoxypropylene glycol, lauryl glucoside, and octylphenol ethoxylate. The treatment liquid of the present invention preferably contains at least one selected from the group consisting of these non-fluorine-based non-ionic surfactants.

<Content of non-fluorine-based nonionic surfactant>> The content of the non-fluorine-based nonionic surfactant in the treatment liquid of the present invention is not particularly limited, but it is usually 1 mass ppm or more relative to the total mass of the treatment liquid . Among them, it is preferable that it is in the range of 1 mass ppm to 0.5 mass% relative to the total mass of the treatment liquid, it is more preferably 10 mass ppm to 0.3 mass %, and it is 50 mass ppm to 0.1 mass% (1000 mass ppm) is further preferred. In the treatment liquid of the present invention, if the content of the non-fluorine-based nonionic surfactant is within this range, the etching rate of the InP layer and the InGaAs layer can be further reduced without impairing the etching rate of the SiO ₂ layer .

(Measurement method/measurement conditions of the content of non-fluorine-based non-ionic surfactant) The content of the non-fluorine-based non-ionic surfactant in the treatment liquid of the present invention can be determined by IC method (ion exchange chromatography), GC/MS method (gas chromatography-mass analysis) or LC/MS (liquid chromatography) -Quality analysis method).

The measurement conditions for the case where the content of the non-fluorine-based non-ionic surfactant in the treatment liquid of the present invention is measured by liquid chromatography-mass spectrometry (LC/MS) method are shown below. Liquid chromatography mass analysis device: UPLC-H-Class, Xevo G2-XS QTof (manufactured by Thermo Fisher Scientific) • LC conditions Device: UPLC H-Class Column: ACQUITY UPLC C8 1.7 μm, 2.1×100 mm Column temperature: 40°C Mobile phase: A: 0.1% formic acid, B: containing 0.1% formic acid MeOH Flow rate: 0.5 mL/min Injection volume: 2 μL • MS conditions Device: Xevo G2-XS Q-Tof Ionization mode: ESI positive/negative Capillary voltage: 1.0 kV/2.5 kV Solvent gas removal: 1000 L/hr, 500°C Sample cone gas: 50 L/hr Injection cone voltage: 40 V (offset 80 V) Collision energy: 2 eV Measuring range: m/z 100-1000 Measurement mode: MS Sensitivity Mode (resolution/30,000) • MS/MS conditions Collision energy Low Energy: 6 eV High Energy: 30 eV to 50 eV (ramp start to end) From the obtained measurement results, the organic impurities belonging to unknown components with m/Z of 300 to 1000 in the organic impurities are classified, and their contents (relative amounts) are also obtained together.

<Additive> The treatment liquid may contain additives within the range that does not impair the characteristics of the treatment liquid of the present invention. Examples of such additives are tetramethylammonium chloride (TMAC1) and ammonium polyacrylate (PAA), but these are not limited. If the treatment liquid of the present invention contains these additives, the value of SiO ₂ ER/InP ER will further increase, and the SiO ₂ selectivity will become better.

<pH adjuster> The treatment liquid may contain a pH adjusting agent as long as the characteristics of the treatment liquid of the present invention are not impaired. The pH adjusting agent is not hydrogen fluoride and its aqueous solution (hydrofluoric acid), ammonium fluoride and its aqueous solution, resist, surfactant, oxidizing agent, and the above additives. Examples of such a pH adjusting agent are methanesulfonic acid (MSA) and 1,8-diazebicyclo[5.4.0]undec-7-ene (DBU), but it is not limited thereto.

<Solvent> The treatment liquid of the present invention may contain a solvent. The solvent is not particularly limited as long as it can be dissolved in the fluorine source compound and the resist. As the solvent, water is preferred. The water that can be used as the solvent of the treatment liquid of the present invention is not particularly limited, but it is preferably high purity. Among them, distilled water, Milli-Q water or RO (reverse osmosis) water is preferred.

<Conductivity> The conductivity of the treatment liquid of the present invention is not particularly limited, but it is preferably 200 mS/cm to 1200 mS/cm, and more preferably 500 mS/cm to 1000 mS/cm. In the treatment liquid of the present invention, if the conductivity is within this range, the defects of SiO ₂ can be further reduced.

The conductivity of the treatment liquid of the present invention is the conductivity (mS/cm) measured using a conductivity meter (conductivity meter (conductivity meter): mobile D-70/ES-70 series, manufactured by HORIBA, Ltd.).

<pH> The pH of the treatment liquid of the present invention is not particularly limited, but it is preferably in the range of 1 to 5, more preferably in the range of 2 to 5, and even more preferably in the range of 2 to 4.5. In the treatment liquid of the present invention, if the pH is within this range, the etching rate of the SiO ₂ layer can be increased and the surface roughness of the InP layer and InGaAs layer can be further suppressed.

The pH of the treatment liquid of the present invention is a pH measured at 23°C using a pH meter (pH meter: mobile D-70 series, manufactured by HORIBA, Ltd.).

[Manufacturing method of treatment liquid] The treatment liquid of the present invention can be produced by mixing and purifying the above components, for example. The purification system preferably uses a filter to filter the treatment liquid.

<Filter processing> The method for producing the treatment liquid of the present invention preferably uses a filter to filter the treatment liquid as the object to be purified. The method of filtering the material to be purified by using a filter is not particularly limited, but it is preferable to pass the material to be purified under or without pressure (through a fluid) with a filter unit having a casing and a filter element accommodated in the casing.

<<pore size of filter>> The pore size of the filter is not particularly limited, and a filter that is generally used as a pore size for filtration of a product to be purified can be used. Among them, from the viewpoint of easily reducing the number of coarse particles contained in the treatment liquid, the pore size of the filter is preferably 200 nm or less, more preferably 100 nm or less, further preferably 50 nm or less, and 20 nm or less Very good, best below 10 nm. The lower limit is not particularly limited, but from the viewpoint of productivity, usually 1 nm or more is preferable. In addition, in this specification, the pore size and pore size distribution of the filter are represented by isopropyl alcohol (IPA) or HFE-7200 ("NOVEC7200", manufactured by 3M, hydrofluoroether, C ₄ F ₉ OC ₂ H ₅ ) The pore size and pore size distribution determined by the bubble point.

Furthermore, the filter can be used alone or in combination with filters with other pore sizes. Among them, from the viewpoint of more excellent productivity, it is preferable to use two or more filters having different pore sizes. In this case, as long as the object to be purified filtered in advance by the filter with a larger pore size passes through the filter with a smaller pore size, clogging of the filter with a smaller pore size can be prevented.

The form of using two or more types of filters with different pore sizes in sequence is not particularly limited, and a method of sequentially arranging filter units along the pipeline for transferring the product to be purified may be mentioned. At this time, if the flow rate per unit time of the object to be purified is to be constant as the entire pipe, a filter unit with a smaller pore size may be subjected to greater pressure than a filter unit with a larger pore size. At this time, the pressure adjustment valve and the damper are arranged between the filter units to make the pressure applied to the filter unit with a small pore size constant, and the filter units containing the same filter are arranged in parallel along the pipeline to increase the filter area as Better. In this way, the number of particles in the chemical solution can be controlled more stably.

＜＜Material of filter＞＞ The material of the filter is not particularly limited, and a material known as a material of the filter can be used. Specifically, in the case of resins, polyamides such as nylon (for example, 6-nylon and 6,6-nylon); polyolefins such as polyethylene and polypropylene; polystyrene; polyamide Imine; polyamidoamide; poly(meth)acrylate; polytetrafluoroethylene, perfluoroalkoxy alkane, perfluoroethylene propylene copolymer, ethylene-tetrafluoroethylene copolymer, ethylene-trifluorochloride Polyfluorocarbons such as ethylene copolymer, polychlorotrifluoroethylene, polyvinylidene fluoride and polyvinyl fluoride; polyvinyl alcohol; polyester; cellulose; cellulose acetate, etc. Among them, from the viewpoint of having more excellent solvent resistance and the obtained chemical solution having more excellent defect suppression performance, it is selected from nylon (of which 6,6-nylon is preferred), polyolefin (wherein polyethylene is (Preferred), poly(meth)acrylate and polyfluorocarbon (of which polytetrafluoroethylene (PTFE) and perfluoroalkoxy alkane (PFA) are preferred.) Better. These polymers can be used alone or in combination of two or more. In addition to resin, diatomaceous earth and glass can also be used. In addition, a polymer (nylon grafted UPE, etc.) obtained by graft copolymerizing polyamide (for example, nylon-6 and nylon-6,6 nylon) on polyolefin (UPE, etc. described later) can be used Filter material.

In addition, the filter may be a surface-treated filter. The method of surface treatment is not particularly limited, and a known method can be used. Examples of the surface treatment method include chemical modification treatment, plasma treatment, hydrophobic treatment, coating, gas treatment, and sintering.

Plasma treatment makes the surface of the filter hydrophilic, which is preferable. The water contact angle on the surface of the filter material hydrophilized as a plasma treatment is not particularly limited, but the static contact angle at 25°C measured by a contact angle meter is preferably 60° or less, and 50° or less is More preferably, 30° or less is further preferable.

As the chemical modification treatment, a method of introducing an ion exchange group into the base material is preferred. That is, as the filter, it is preferable to use each of the materials mentioned above as a base material and introduce ion exchange groups into the base material. Typically, a filter provided with a layer containing a substrate containing ion-exchange groups on the surface of the above substrate is preferable. The surface-modified base material is not particularly limited. From the viewpoint of easier production, a filter in which ion exchange groups are introduced into the above polymer is preferable.

[Approach] The treatment method of the invention is a treatment method using the treatment liquid of the invention.

The processing method of the present invention also comprises selectively removing the InP layer has In _x P is formed in the processing method and the sum of SiO SiO ₂ SiO ₂ layer of the laminate containing the layers ₂ on an InP layer of the present invention comprises The step of contacting the treatment liquid and the laminate. Here, x is a real number greater than 0 and less than 1.

The processing method of the present invention is also to selectively remove the InP layer containing In _x P and the coating layer formed on the InP layer, a part of the region of the coating layer is formed of the SiO ₂ layer, and other regions are made of In _z Ga _{( 1 -z )} The method for processing the SiO ₂ layer of the laminate formed by the InGaAs layer of As includes the contacting step of bringing the treatment liquid of the present invention into contact with the laminate. Among them, x and z are independently real numbers greater than 0 and 1 or less.

Hereinafter, the details will be described with reference to FIGS. 1 to 8.

<Light-receiving element> FIG. 1 shows a cross-sectional structure of a light receiving element (light receiving element 1). The light-receiving element 1 is, for example, an infrared sensor suitable for using a compound semiconductor (III-V group semiconductor), and includes a plurality of light-receiving unit regions (referred to as pixels P) arranged two-dimensionally. In addition, in FIG. 1, the cross-sectional structure of the part corresponding to two pixels P is shown.

<<Structure of light-receiving element>> The light receiving element 1 is provided with a photoelectric conversion layer 12 including a compound semiconductor (III-V group semiconductor). In this light-receiving element 1, for example, a plurality of photoelectric conversion layers 12 are formed on one surface (surface S1) of the substrate 11, and electrodes 13 are electrically connected to each photoelectric conversion layer 12. On the surface (surface S2) on the light incident side of the substrate 11, an on-wafer lens 17 is formed for the pixel P. A protective film 16 is formed on the electrode 13 side (the side opposite to the light incident side) of the light receiving element 1.

In this light-receiving element 1, a plurality of photoelectric conversion layers 12 are separated from each other (island-like) in plan view. An insulating film 15 is formed so as to surround the plurality of photoelectric conversion layers 12 respectively. A passivation film 14 is formed to cover at least a part of each photoelectric conversion layer 12 (for example, the side surface 12b). The insulating film 15 is formed so as to fill the area between the photoelectric conversion layers 12 covered by the passivation film 14 (the area between the pixels).

Furthermore, a silicon semiconductor substrate formed with a pixel circuit for reading signals from each pixel P, various wirings, and the like is stacked on the electrode 13. The electrode 13 is electrically connected to various circuits formed on the silicon semiconductor substrate by, for example, bumps or through holes. Hereinafter, the configuration of each part will be described.

The substrate 11 is composed of, for example, a p-type or n-type compound semiconductor (for example, InP (Indium Phosphorus)). Here, the photoelectric conversion layer 12 is in contact with the substrate 11 and is formed on the surface S1 of the substrate 11. As the material of the layer interposed between the substrate 11 and the photoelectric conversion layer 12, for example, InAlAs, Ge, Si, GaAs and InP and other semiconductor materials, it is preferable to select a lattice match between the substrate 11 and the photoelectric conversion layer 12.

The photoelectric conversion layer 12 is, for example, a compound semiconductor (for example, a p-type or n-type compound semiconductor) including a compound semiconductor that absorbs a wavelength (infrared IR) in the infrared region and generates charges (electrons and holes). In the embodiment, the photoelectric conversion layer 12 is provided separately for each pixel P.

The compound semiconductor used for the photoelectric conversion layer 12 is, for example, InGaAs (Indium Gallium Arsenide). The composition is, for example, In _x Ga _(1-x) As (x: 0<x≦1). Among them, in order to further obtain sensitivity in the infrared region, x ≥ 0.4 is preferable. As an example of the composition of the photoelectric conversion layer 12 lattice-matched to the substrate 11 made of InP, In _0.53 Ga _0.47 As can be mentioned. Examples of the impurity element contained in the photoelectric conversion layer 12 include zinc (Zn) and silicon (Si).

The electrode 13 is an electrode that supplies a voltage for reading charges (holes or electrons) generated in the photoelectric conversion layer 12 and is formed in each pixel P. Examples of the constituent material of the electrode 13 include titanium (Ti), tungsten (W), titanium nitride (TiN), platinum (Pt), gold (Au), germanium (Ge), nickel (Ni), and aluminum Any one of (Al) or an alloy containing at least one of them.

This electrode 13 is connected to a selective region on the upper surface (surface 12a) of the photoelectric conversion layer 12, for example. Here, the electrode 13 is provided in each pixel P and formed in the opening h1 (first opening) provided in the passivation film 14 and the protective film 16, and is in contact with the surface 12 a of the photoelectric conversion layer 12 through the opening h1. Among them, a plurality of electrodes 13 may be arranged for one pixel P. In addition, when a plurality of electrodes 13 are arranged on one pixel P, some of these may include electrodes (virtual electrodes) that do not actually contribute to the charge readout.

The passivation film 14 is formed by covering at least a part of the surface of the photoelectric conversion layer 12 (for example, the side surface 12b). In the example described here, the surface of the photoelectric conversion layer 12 is covered except for the portion facing the substrate 11 (specifically, the surface 12c in contact with the surface S1 of the substrate 11) and its connection to the electrode 13 The part (specifically, the part that is in contact with the electrode 13 in the surface 12a) is formed.

The passivation film 14 is configured to include an insulator or a semiconductor that is less likely to form defects at its interface with the compound semiconductor included in the photoelectric conversion layer 12. As an example of such an insulator, a high dielectric constant material such as aluminum oxide (Al ₂ O ₃ ) or silicon nitride (SiN) may be mentioned. In the case of using a semiconductor in the passivation film 14, it is preferable to select a material having a band gap larger than the photoelectric conversion layer 12. As an example, when the photoelectric conversion layer 12 contains In _0.53 Ga _0.47 As (band gap 0.74 eV), the passivation film 14 is preferably InP (band gap 1.34 eV), InAlAs, or Si.

The insulating film 15 is configured to contain an oxide such as silicon oxide (SiO _x ), for example. The insulating film 15 is formed to surround a plurality of photoelectric conversion layers 12 respectively, and is used to electrically separate the photoelectric conversion layer 12 for each pixel P. In the example described here, as described above, the insulating film 15 is formed so as to fill the area between the photoelectric conversion layers 12 covered by the passivation film 14. In other words, the passivation film 14 is interposed between the insulating film 15 and the photoelectric conversion layer 12, and the insulating film 15 is formed in a structure that does not directly contact the photoelectric conversion layer 12.

The protective film 16 is configured to contain an inorganic insulating material (for example, at least one of silicon nitride (SiN), aluminum oxide (Al ₂ O ₃ ), and hafnium oxide (HfO ₂ )). The protective film 16 may be a single-layer film or a laminated film.

The on-wafer lens 17 is for collecting incident light (infrared rays) on the photoelectric conversion layer 12. The lens 17 on the wafer can be provided as needed. In addition, the shape of the lens 17 on the wafer is not limited to those shown. Furthermore, when the light receiving element 1 is used not only for infrared detection but also for visible light detection, for example, a color filter may be further arranged between the substrate 11 and the on-wafer lens 17.

<<Manufacturing method of light receiving element>> The light receiving element 1 can be manufactured as follows, for example. 2 to 8 show the steps of manufacturing the light-receiving element 1 in the order of steps. In addition, in FIGS. 2 to 8, for simplicity, only a region corresponding to one pixel P is shown.

First, for example, a photoelectric conversion layer 12 containing the above-mentioned materials is formed in a selective region on a substrate 11 (first substrate) made of InP. At this time, first, as shown in FIG. 2, an oxide film 51 is patterned on the surface S1 of the substrate 11. Specifically, for example, after the oxide film 51 made of silicon oxide is formed on the surface S1 of the substrate 11, the opening 51 a (second opening) is formed using, for example, photolithography and dry etching. A plurality of openings 51a are formed for each pixel P.

Next, as shown in FIG. 3, for example, the photoelectric conversion layer 12 containing InGaAs is formed in the opening 51a by selective epitaxial growth. By growing InGaAs on the substrate 11 made of InP, it is easy to lattice match InP and InGaAs, so that crystal defects in the photoelectric conversion layer 12 can be suppressed to a minimum.

Thereafter, as shown in FIG. 4, for example, the portion of the photoelectric conversion layer 12 that grows beyond the upper surface of the oxide film 51 is removed by CMP (Chemical Mechanical Polishing), and the upper surface (surface 12a) is planarized.

Next, as shown in FIG. 5, for example, the oxide film 51 is selectively removed by etching. At this time, a chemical solution capable of ensuring an etching selection ratio between the substrate 11 (InP) and the photoelectric conversion layer 12 (InGaAs) and the oxide film 51 is used. Examples of such chemical solutions include hydrofluoric acid-based chemical solutions. In this way, the photoelectric conversion layer 12 can be formed in the selective region on the substrate 11. That is, a plurality of photoelectric conversion layers 12 can be formed on the substrate 11 in islands.

Next, as shown in FIG. 6, for example, a passivation film 14 containing the above-mentioned materials is formed by CVD (Chemical Vapor Deposition) or ALD (Atomic Layer Deposition). Thereby, the passivation film 14 is formed by covering the surface 12a and the side surface 12b of the photoelectric conversion layer 12.

After that, as shown in FIG. 7, an insulating film 15 made of the above-mentioned materials is formed. Specifically, for example, after forming the insulating film 15 so as to fill the gap between the photoelectric conversion layers 12 covered by the passivation film 14 using CVD or the like, for example, CMP is used to planarize the surface.

Next, as shown in FIG. 8, an electrode 13 made of the above-mentioned materials is formed. Specifically, first, the protective film 16 made of the above-mentioned materials is formed over the entire surface of the passivation film 14 and the insulating film 15 using, for example, CVD or sputtering. Next, a portion corresponding to the surface 12 a of the photoelectric conversion layer 12 in the passivation film 14 and the protective film 16 is opened (the opening h1 is formed), and the electrode 13 is formed in the opening h1. In detail, for example, after forming the electrode 13 made of the above-mentioned material by filling the opening h1 using CVD, plasma CVD, thermal CVD, ALD, or vapor deposition method, it is patterned using photolithography and etching. Thereby, in the surface of the photoelectric conversion layer 12, portions other than the portion facing the substrate 11 and the connection portion with the electrode 13 are covered with the passivation film 14.

Finally, by forming or bonding the on-wafer lens 17 on the surface S2 side of the substrate 11, the light receiving element 1 shown in FIG. 1 is completed.

<<Method of using the treatment liquid of the present invention>> In order to selectively remove the oxide film 51 from the state where the photoelectric conversion layer 12 and the oxide film 51 are formed on the substrate 11 containing InP as shown in FIG. In the state shown, the treatment liquid of the present invention can be used as an etching treatment liquid when the oxide film 51 containing SiO _{2 is} selectively removed.

The treatment liquid of the present invention can suppress the surface of the substrate 11 containing InP (equivalent to the InP layer containing In _x P) and the photoelectric conversion layer 12 containing InGaAs (the equivalent of the InGaAs layer containing In _z Ga _(1-z) As) Roughness can also suppress the generation of defects of SiO ₂ , so defective products are rarely generated. When the processing liquid of the present invention contains a non-fluorine-based non-ionic surfactant, the non-fluorine-based non-ionic surfactant can further suppress the dissolution of InP and InGaAs, and therefore can dissolve the InP-containing substrate 11 (equivalent to InP layer of In _x P) and photoelectric conversion layer 12 containing InGaAs (equivalent to InGaAs layer containing In _z Ga _(1-z) As), the insulating film 51 (equivalent to SiO ₂ containing SiO ₂ ) is selectively removed _2nd floor). [Example]

[Examples 1 to 46, Comparative Examples 1 to 5] <Manufacture of processing liquid> Each component was mixed with the composition shown in Table 1, and it filtered by the HDPE (high density polyethylene) filter which has a pore size shown in Table 2 once or twice, and the processing liquid was produced.

<pH, conductivity> The treatment liquids of Examples 1 to 46 and Comparative Examples 1 to 5 were measured for pH and conductivity.

＜＜pH measurement＞＞ The pH system was measured at 23°C using a pH meter (pH meter: mobile D-70 series, manufactured by HORIBA, Ltd.). The "pH" column of Table 1 shows the pH of each treatment liquid obtained by measurement.

<<Measurement of conductivity>> The conductivity was measured using a conductivity meter (conductivity meter (conductivity meter): mobile D-70/ES-70 series, manufactured by HORIBA, Ltd.). The column of “Conductivity” in Table 1 shows the conductivity of each treatment liquid obtained by measurement. In addition, "<1" in the table means less than 1.

[Table 1-1]

[Table 1-2]

[Table 1-3]

In Table 1, TMAC1, MSA, and DBU have the meanings shown below, respectively. TMACl...tetramethylammonium chloride MSA... methanesulfonic acid DBU……1,8-Diacbicyclo[5.4.0]undec-7-ene

[table 2-1]

[Table 2-2]

[Table 2-3]

<Measurement of coarse particles> Regarding the treatment liquids of Examples 1 to 46 and Comparative Examples 1 to 5, the number of particles with a particle size of 0.10 μm or more per 1 mL of the treatment liquid was measured using a liquid particle counter (KS-18F, manufactured by RION Co., Ltd.) A (pieces/mL) and the number of particles with a particle size of 0.05 μm or more per 1 mL of the processing solution B (pieces/mL). Next, A/B was calculated based on A and B obtained by measurement. The column of "coarse particles" in Table 3 shows the number A (particles/mL) of particles with a particle size of 0.10 μm or more per 1 mL of the processing solution, and the number B (particles) of particles with a particle size of 0.05 μm or more per 1 mL of the processing solution /mL) and the ratio A of the number of particles (particles/mL) of 0.10 μm or more per 1 mL of processing solution to the number of particles (particles/mL) of 0.05 μm or more per 1 mL of processing solution /B. In addition, A/B rounds the fourth digit after the decimal point and finds it to the third digit after the decimal point.

<Measurement of oxidant and metal ion content> The treatment liquids of Examples 1 to 46 and Comparative Examples 1 to 5 were measured using a triple quadrupole ICP-MS (Inductively Coupled Plasma Mass Analysis Device) (Agilent 8800 series, manufactured by Agilent Technologies, Inc.) with a standard electrode potential greater than 0V The content of metal ions C (mass ppt). In addition, regarding these treatment liquids, the content D (mass ppt) of the oxidizing agent was measured by the aforementioned measurement method. Table 3 shows the content C (mass ppt) of metal ions with a standard electrode potential greater than 0 V in the column of “metal ions”, and the content D (mass ppt) of oxidants in the column of “oxidant”.

<Calculation of content ratio> The treatment liquids of Examples 1 to 46 and Comparative Examples 1 to 5 are based on the content X (mass %) of fluorine atoms, the content Y (mass %) of the resist, and the content C of metal ions with a standard electrode potential greater than 0 V (Mass ppt) and oxidizer content D (mass ppt) calculated the following content ratios. • The value of the ratio of the content X of fluorine atoms to the total content C+D of metal ions and oxidants whose standard electrode potential is greater than 0 V X/(C+D) •The value of the ratio of the content Y of the resist to the total content C+D of the metal ions and oxidants whose standard electrode potential is greater than 0 V Y/(C+D) • The value of the ratio of the content X of fluorine atoms to the content Y of resist X/Y The column of “content ratio” in Table 3 shows X/(C+D), Y/(C+D), and X/Y, respectively.

[Table 3-1]

[Table 3-2]

[Table 3-3]

In Table 3, A, B, C, D, X, and Y have the meanings shown below, respectively. A……Number of particles with a particle size of 0.10 μm or more per 1 mL of processing solution (pieces/mL) B……Number of particles with a particle size of 0.05 μm or more per 1 mL of processing solution (pieces/mL) C... The content of metal ions with a standard electrode potential greater than 0 V (mass ppt) D……Content of oxidant (mass ppt) X……Content of fluorine atom (mass %) Y……Content of resist (mass %)

<Evaluation test><<etchingrate>> (Production of test substrate) InP, InGaAs or SiO ₂ was vapor-deposited on a commercially available silicon substrate (diameter: 8 inches) to form a film with a thickness of 100Å. The etching rate (ER) (Å/min) was calculated by measuring the film thickness before and after the etching process using ellipsometry (using a spectroscopic ellipsometer, JA Woollam Japan. Vase). The average value of 5 places was used (measurement condition measurement range: 1.2-2.5 eV, measurement angle: 70, 75 degrees).

＜＜InGaAs layer surface roughness＞＞ Using the processing solutions of Examples 1 to 46 and Comparative Examples 1 to 5, a substrate having a 100 Å InGaAs layer formed on a commercially available silicon substrate (diameter: 8 inches) was etched for a time equivalent to 10 Å InGaAs layer removal deal with. The silicon substrate after the treatment was observed using an atomic force microscope (manufactured by Hitachi High-Technologies Corporation), and the surface roughness (Ra) was evaluated. The evaluation was performed according to the following criteria. A Ra is less than 0.2 Å in the measurement area of 1.0 μm□ B In the measurement area of 1.0 μm□ Ra is more than 0.2 Å and less than 0.5 Å C In the measurement area of 1.0 μm□ Ra is more than 0.5 Å and less than 1.0 Å D Ra is 1.0Å or more in the measurement area of 1.0 μm□

＜＜InP layer surface roughness＞＞ The processing solution of Examples 1 to 46 and Comparative Examples 1 to 5 was used to remove a substrate with a 100 Å InP layer formed on a commercially available silicon substrate (diameter: 8 inches) for a time equivalent to 10 Å of the InP layer. Etching process. The silicon substrate after the treatment was observed using an atomic force microscope (manufactured by Hitachi High-Technologies Corporation), and the surface roughness (Ra) was evaluated. The evaluation was performed according to the following criteria. A Ra is less than 0.2 Å in the measurement area of 1.0 μm□ B In the measurement area of 1.0 μm□ Ra is more than 0.2 Å and less than 0.5 Å C In the measurement area of 1.0 μm□ Ra is more than 0.5 Å and less than 1.0 Å D Ra is 1.0 Å or more in the measurement area of 1.0 μm□

<Defects of SiO ₂ >> Using the processing solutions of Examples 1 to 46 and Comparative Examples 1 to 5, a 100Å InP layer was formed on a commercially available silicon substrate (diameter: 8 inches) and further on the InP layer The substrate with the 50Å SiO ₂ layer formed was etched to remove the SiO ₂ layer. A defect inspection device (Surfscan XP2, manufactured by KLA-Tencor) was used to inspect the processed silicon substrate, and the defect performance was evaluated based on the amount of residue remaining on the substrate. The evaluation was performed according to the following criteria. A The number of defects is less than 50 B The number of defects is more than 50 and less than 100 C The number of defects is more than 100 and less than 200 D The number of defects is more than 200

[Table 4-1]

[Table 4-2]

[Table 4-3]

In Table 4, the symbols described in the column of etching rate have the following meanings. SiO ₂ ER... Etching speed of SiO ₂ layer InP ER... Etching speed of InP layer InGaAs ER... Etching speed of InGaAs layer

[Explanation of Results] With respect to the treatment liquids of Examples 1 to 46 and Comparative Examples 1 to 5, the etching rate of the SiO ₂ layer, InP layer and InGaAs layer, and the surface roughness and SiO _{2 of the} InP layer and InGaAs layer were evaluated. Defects. Treatment liquid of Example 1 to 46 and are capable of selectively removing defects on the surface of SiO ₂ SiO ₂ and InP layer roughness is suppressed. Furthermore, the surface roughness of the InP layer, the surface roughness of the InGaAs layer, and the defects of SiO ₂ of any of the treatment liquids of Examples 1 to 46 are all at a low level, and it is considered that they will not adversely affect the steps after the removal of the SiO ₂ layer .

[Example 9 3,5 ~] Evaluation 3 SiO defects and 6 to 8 in Example ₂ is A or B, the other hand, the defect evaluation SiO 5 and 9 of Example ₂ is C. In Examples 3 and 6 to 8 in which the content of fluorine atoms is in the range of 0.01% by mass to 15% by mass, the defects of SiO ₂ are further suppressed compared to Examples 5 and 9 outside the range.

The evaluation of the defects of SiO ₂ in Examples 6 and 7 is A, whereas the evaluation of the defects of SiO ₂ in Examples 3, 5, 8 and 9 is B or C. The values of the ratio of fluorine atom content X to the total content of metal ions and oxidants (C+D) are in the range of 20,000 to 10,000,000 in Examples 6 and 7 and out of the range of Examples 3, 5, 8 and 9 In comparison, the defects of SiO ₂ are further suppressed.

[Examples 3, 10 to 14] The evaluation of the surface roughness of the InP layer and the surface roughness of the InGaAs layer of Examples 3 and 11 to 13 was A or B, whereas the surface roughness of the InP layer of Example 10 And the surface roughness of the InGaAs layer was evaluated as C. In addition, the evaluation of the defects of SiO ₂ in Examples 3 and 11 to 13 was A or B, while the evaluation of the defects of SiO ₂ in Example 14 was C. The surface roughness of the InP layer and the surface roughness of the InGaAs layer are further obtained in Examples 3 and 11 to 13 where the content of the resist is in the range of 0.01% by mass to 1% by mass compared to Example 10 outside the range Suppression, compared with Example 14, the defects of SiO ₂ were further suppressed.

The evaluation of the surface roughness of the InP layer and the surface roughness of the InGaAs layer of Examples 11, 12, and 14 are both A. In contrast, the surface roughness of the InP layer and the surface of the InGaAs layer of Examples 3, 10, and 13 The roughness was evaluated as B or C. Examples 11, 12, and 14 in which the ratio of the content Y of the resist to the total content (C+D) of metal ions and oxidants is in the range of 40000 to 5000000 and Examples 3, 10, and 13 outside the range In contrast, the surface roughness of the InP layer and the surface roughness of the InGaAs layer are further suppressed.

[Examples 3, 5 to 14] Examples 3, 6 to 9 and 12 to 14 with the value X/Y of the ratio of the fluorine atom content X to the resist content Y in the range of 0.01 to 50 In addition to Examples 5, 10, and 11, the value of SiO ₂ ER/InP ER was further increased, and the SiO ₂ selectivity was further improved.

[Examples 3, 43 to 46] Examples 43 to 46 have superior SiO ₂ selectivity compared to Example 3, and the surface roughness of the InP layer and the surface roughness of the InGaAs layer are further suppressed.

1‧‧‧Receiving element 11‧‧‧ substrate 12‧‧‧Photoelectric conversion layer 12a‧‧‧plane (upper surface of photoelectric conversion layer 12) 12b‧‧‧Side (side of photoelectric conversion layer 12) 12c‧‧‧plane (the plane contacting the plane S1 of the substrate 11) 13‧‧‧electrode 14‧‧‧Passive film 15‧‧‧Insulating film 16‧‧‧Protection film 17‧‧‧on-chip lens 51‧‧‧Oxide film 51a‧‧‧ opening P‧‧‧ pixels S1‧‧‧plane (one side of substrate 11) S2‧‧‧plane (the surface of the substrate 11 on the light incident side) h1‧‧‧ opening

FIG. 1 is a cross-sectional view showing the structure of a light-receiving element. FIG. 2 is a cross-sectional view for explaining a step of the method of manufacturing the light-receiving element shown in FIG. 1. FIG. 3 is a cross-sectional view showing the next step of FIG. 2. FIG. 4 is a cross-sectional view showing the next step of FIG. 3. FIG. 5 is a cross-sectional view showing the next step of FIG. 4. 6 is a cross-sectional view showing the next step of FIG. 5. 7 is a cross-sectional view showing the next step of FIG. 6. 8 is a cross-sectional view showing the next step in FIG. 7.

1‧‧‧Receiving element

11‧‧‧ substrate

12‧‧‧Photoelectric conversion layer

12a‧‧‧plane (upper surface of photoelectric conversion layer 12)

12b‧‧‧Side (side of photoelectric conversion layer 12)

12c‧‧‧plane (the plane contacting the plane S1 of the substrate 11)

13‧‧‧electrode

14‧‧‧Passive film

15‧‧‧Insulating film

16‧‧‧Protection film

17‧‧‧on-chip lens

P‧‧‧ pixels

S1‧‧‧plane (one side of substrate 11)

S2‧‧‧plane (plane on the light incident side of the substrate 11)

h1‧‧‧ opening

Claims (18)

A treatment liquid containing hydrogen fluoride and resist, The number of coarse particles with a particle size of 0.10 μm or more per 1 mL of the treatment solution is less than 100 particles/mL, The number of coarse particles with a particle diameter of 0.05 μm or more per 1 mL of the treatment solution is less than 500 particles/mL, and The value of the ratio of the number of coarse particles with a particle size of 0.10 μm or more per 1 mL of the processing liquid to the number of coarse particles with a particle size of 0.05 μm or more per 1 mL of the processing liquid is greater than 0.010 and less than 1.000. The treatment fluid as described in item 1 of the patent application scope, where The treatment liquid further contains ammonium fluoride. The treatment fluid as described in item 1 or 2 of the patent application scope, where The content of fluorine atoms is in the range of 0.01% by mass to 15% by mass relative to the total mass of the treatment liquid. The treatment liquid as described in item 1 or item 2 of the scope of the patent application, which further contains at least one selected from the group consisting of metal ions and oxidants whose standard electrode potential is greater than 0 V, The total content of the metal ion and the oxidizing agent is 10 mass ppb or less with respect to the total mass of the treatment liquid. The treatment fluid as described in item 4 of the patent application scope, in which The value of the ratio of the content of fluorine atoms to the total content of the metal ion and the oxidant is in the range of 20,000 to 10,000,000. The treatment fluid as described in item 4 of the patent application scope, in which The value of the ratio of the content of the resist to the content of the metal ion and the oxidant is in the range of 40,000 to 5,000,000. The treatment liquid as described in item 1 or 2 of the patent application has a pH in the range of 1 to 5. The treatment fluid as described in item 1 or 2 of the patent application scope, where The resist contains at least one selected from the group consisting of compounds having mercapto groups, azole derivatives, thiazole derivatives, hydroxycarboxylic acids, reducing agents, and sugars. The treatment fluid as described in item 1 or 2 of the patent application scope, where The resist contains selected from 2-mercaptopyridine, mercaptosuccinic acid, 2-aminoethanethiol, bismuth mercaptan, 2-mercaptobenzimidazole, 2-amino-5-mercapto-1,3,4- Thiadiazole, 3-amino-5-mercapto-1,2,4-triazole, 5-mercapto-1H-tetrazole, 2-aminobenzimidazole, 3-amino-1,2,4- Triazole, 3,5-diamino-1,2,4-triazole, tetrazole, 5-aminotetrazole, citric acid, gluconic acid, DL-tartaric acid, galactaric acid, oxalic acid, diethyl At least one of the group consisting of hydroxylamine, ascorbic acid, fructose, glucose, and ribose. The treatment fluid as described in item 1 or 2 of the patent application scope, where The content of the resist is in the range of 0.01% by mass to 1.0% by mass relative to the total mass of the treatment liquid. The treatment fluid as described in item 1 or 2 of the patent application scope, where The value of the ratio of the content of fluorine atoms to the content of the resist is in the range of 0.01 to 50. The treatment liquid as described in item 1 or 2 of the scope of patent application has a conductivity in the range of 200 mS/cm to 1200 mS/cm. The treatment liquid as described in Item 1 or Item 2 of the patent application scope further contains a non-fluorine-based non-ionic surfactant. The treatment fluid as described in item 13 of the patent application scope, in which The non-fluorine-based nonionic surfactant contains at least one selected from the group consisting of polyoxyethylene lauryl ether, polyoxyethylene polyoxypropylene glycol, lauryl glucoside, and octylphenol ethoxylate. The treatment fluid as described in item 13 of the patent application scope, in which The content of the non-fluorine-based non-ionic surfactant is in the range of 1 mass ppm to 0.5 mass% relative to the total mass of the treatment liquid. A treatment method using the treatment liquid as described in any one of claims 1 to 14. A processing method, which is selectively removed with containing InP layer In _x P sum ₂ layer formed SiO on the InP layers containing SiO SiO ₂ of _two layers of laminate, and includes patent scope Item 1 as The contact step of the treatment liquid according to any one of the items 15 to contact with the laminate, wherein x is a real number greater than 0 and 1 or less. A processing method that selectively removes an InP layer containing In _x P and a coating layer formed on the InP layer, a part of the region of the coating layer is formed of a SiO ₂ layer, and other regions are made of In _z Ga _{(1- z)} The SiO ₂ layer of the laminate formed by the InGaAs layer of As, and includes the contacting step of contacting the treatment liquid described in any one of the patent application items 1 to 15 with the laminate, where x and z are independently real numbers greater than 0 and less than 1.

Images