CN116120936A

CN116120936A - Etching liquid medicine and preparation method and application thereof

Info

Publication number: CN116120936A
Application number: CN202211327345.9A
Authority: CN
Inventors: 周煜; 黄建东; 章晓冬
Original assignee: Shanghai Tiancheng Chemical Co ltd
Current assignee: Shanghai Tiancheng Chemical Co ltd
Priority date: 2022-10-27
Filing date: 2022-10-27
Publication date: 2023-05-16

Abstract

The invention provides an etching liquid and a preparation method and application thereof, wherein the etching liquid comprises the following components in parts by weight: 100-150 parts of sulfuric acid, 30-60 parts of hydrogen peroxide, 0.1-15 parts of hydrogen peroxide stabilizer, 1-5 parts of organic acid, 0.005-0.2 part of amino acid compound, 0.001-0.05 part of noble metal salt, 1-10 parts of complexing agent and 0.001-0.5 part of corrosion inhibitor. The etching liquid medicine provided by the invention can effectively etch and remove the copper layer in the metal material, can treat the dense fine circuit board, and has the characteristics of no residual copper of bottom copper after etching, no undercut of circuit, square line shape, small side etching and the like.

Description

Etching liquid medicine and preparation method and application thereof

Technical Field

The invention belongs to the technical field of chemical etching, and particularly relates to an etching liquid medicine, a preparation method and application thereof.

Background

With the rapid development of 5G technology, the demands for products such as servers, routers, wiGig (wireless gigabit), automotive radar and the like are increasing, and the demands for carrier boards are increasing. The number of carrier plate manufacturers in China is increased, the yield is increased, the processing requirements on products are improved continuously, and the precision of related professional chemicals required in the carrier plate production process is increased greatly. The carrier production process generally employs a semi-additive process (SAP) and a modified semi-additive process (mspa). The mSAP process is widely applied because of high process precision and low requirements on equipment and materials, and the wiring method is generally to firstly thin copper foil on the surface of the pressed copper-clad plate, then drill holes, remove glue and metalize holes, then coat a photosensitive resist layer on the copper surface and sequentially expose, develop, pattern electroplate, remove film, etch and the like to form final lines and patterns.

In addition, with the rapid development of electronic consumer products, the volume of electronic products is continuously reduced, the functions are continuously diversified, and the circuit board is promoted to develop towards high densification, miniaturization and multilayering, so that the circuit miniaturization degree is also higher and higher, and the line width/line distance of the circuit is generally reduced from 150 μm/150 μm and below to 50 μm/50 μm and even reaches 25 μm/25 μm. Therefore, etching solutions play an important role in the carrier manufacturing process. If the etching effect is poor, side etching is serious, so that line width is narrowed, section of the line is deformed, signal transmission resistance is increased, and signal transmission speed and integrity are affected. In addition, due to the difference of copper lattices of the base layer copper and the electroplated layer copper, undercut is easy to generate, the undercut seriously causes circuit disconnection to cause circuit even floating, the reliability is seriously affected, the traditional acid copper or alkali copper etching liquid medicine can not meet the precision requirement, and even if vacuum etching equipment is adopted, the processing yield is difficult to ensure.

CN110904456a discloses a copper etching liquid medicine, a preparation method and application thereof. The copper etching liquid comprises the following components: the acid calculates 100-200g/L of tetravalent cerium salt, 200-500g/L of tetravalent cerium salt and 0.01-10g/L of auxiliary agent according to the solute; the solvent of the copper etching liquid medicine is water; the auxiliary agent is any one or a mixture of at least two of imidazole compounds, sulfonic acid compounds and polyamine. The copper etching liquid medicine can ensure high etching efficiency, and simultaneously satisfies high copper dissolution amount of the etching liquid medicine, so that the copper etching liquid medicine is excellent in stability in the etching process, and the problems of large copper side etching amount and undercut of bottom copper can be avoided to a great extent.

CN104120428A discloses a microetching chemistry treatment agent that recycles copper and copper alloy surfaces; the composite material comprises the following components in percentage by weight: 1% -12% of sulfuric acid and/or nitric acid; 1.5% -25% of ferric sulfate and/or ferric nitrate; 0.002% -0.1% of additive A; the balance of deionized water; the additive A is one or more than two of sodium polydithio-dipropyl sulfonate, sodium 3-mercapto-1-propane sulfonate, sodium N, N-dimethyl dithio carbonyl propane sulfonate, isothiourea propane sulfonate inner salt and sodium 3- (benzothiazole-2-mercapto) -propane sulfonate. The microetching chemical treatment agent improves the electrolysis efficiency and reduces the energy consumption; the formation of cathode copper nodules is avoided, the risk of breakdown and damage of the anode is reduced, and the production control and operation are greatly simplified.

CN107747094a discloses an acidic etching liquid additive and acidic etching liquid, the additive comprises 1-200 parts of nonionic surfactant and 1-200 parts of stabilizer, the stabilizer is at least one of urea, mercaptan and bromide containing sulfur; the acidic etching liquid comprises etching liquid base liquid and the additive. The product of the invention can be well applied to producing printed circuit boards with thicker copper (such as copper with the thickness of 70 mu m or more) or larger area to be etched, and the problem of unstable or slow etching speed can not occur.

The prior art discloses etching liquid for etching copper layers in circuit boards, and the common etching liquid mainly has the following three problems: firstly, the side etching is serious, so that the line width loss is larger; secondly, for the dense circuit board, in the etching process, the dense thin circuit area is easy to cause incomplete etching due to poor liquid medicine exchange, so that a short circuit phenomenon occurs in the product using process, and the circuit has a narrow upper part and a wide lower part due to fast top exchange and slow bottom exchange of the circuit due to the liquid medicine exchange, so that the signal transmission resistance is increased; thirdly, due to the difference of the crystallization of the bottom copper and the electroplated copper, undercut is easy to generate in the etching process, and the undercut seriously causes circuit disconnection and even floating, thereby seriously affecting the reliability.

Therefore, developing an etching solution which can process a dense fine circuit board, has no residual copper on bottom copper after etching, has no undercut on a circuit, has a square section of the circuit after etching, and has low copper loss on the circuit is an important research point in the field.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide an etching liquid and a preparation method and application thereof.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

in a first aspect, the present invention provides an etching solution comprising the following components in parts by weight:

the etching liquid provided by the invention is mainly applied to metal etching, in particular to etching process in the manufacturing process of a high-end circuit board, wherein the bottom copper of the circuit board can be sputtered copper, chemical copper or electrolytic copper, and is preferably electrolytic copper. The etching water provided by the invention can obviously reduce the etching rate ratio of electroplated copper to electrolytic copper, reduce the copper loss of a circuit while removing bottom copper, and optimize the line type of the circuit, the line width of the etched circuit and the line height to meet the requirements. The hydrogen peroxide stabilizer and the corrosion inhibitor are added, so that the etching rate can be effectively controlled, and the rapid reduction of the etching rate caused by the decomposition of hydrogen peroxide in the etching process is avoided, and the etching effect is influenced; the organic acid and amino acid compound can form an insoluble complex with noble metal ions to be adsorbed on the copper surface, and in the etching process, a spraying mode is adopted, and complex films on the surfaces of the copper and the copper lines are easily washed away by liquid medicine under the action of pressure, so that the etching in the vertical direction can be normally carried out, the complex adsorbed on the side of the copper lines is not easily broken through, and the complex film acts as a bank protection agent, thereby effectively reducing the side etching rate and avoiding line thinning; meanwhile, in the etching process, the insoluble complex is distributed in a gradient way on the side edge due to the reason of liquid medicine exchange, namely, the uppermost end is adsorbed more, the etching rate is lowest, the bottom end is adsorbed less, the etching rate is fastest, and the section of the circuit before etching is generally narrow at the top and wide at the bottom, so that the line width difference between the upper line and the lower line after etching can be reduced, and the line type is optimized. The corrosion inhibitor can be chemically adsorbed at the corner of the circuit, so that the radian of the circuit is reduced. Complexing agentCan complex Cu ² ⁺ Maintaining Cu in etching liquid ²⁺ The concentration is stable, the etching rate is stable, the copper capacity is increased, the groove changing frequency is reduced, and the sewage discharge is reduced. In conclusion, the etching liquid obtained by adopting the technical scheme of the invention can be used for processing the circuit board with dense fine lines, and has the characteristics of no residual copper of the bottom copper after etching, no undercut of the line, square line, small side etching and the like.

The sulfuric acid is 100-150 parts, for example, 110 parts, 120 parts, 130 parts or 140 parts, etc.

The hydrogen peroxide is 30-60 parts, for example, 35 parts, 40 parts, 45 parts, 50 parts or 55 parts, etc.

The hydrogen peroxide stabilizer is 0.1-15 parts, for example, 0.2 parts, 0.4 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts or 14 parts, etc.

The organic acid is 1-5 parts, for example, 2 parts, 3 parts, 4 parts, or the like.

The amino acid compound may be 0.005-0.2 parts, for example, 0.002 parts, 0.004 parts, 0.006 parts, 0.008 parts, 0.01 parts, 0.02 parts, 0.04 parts, 0.1 parts, 0.12 parts, 0.14 parts, 0.18 parts, etc.

The noble metal salt is 0.001 to 0.05 part, for example, 0.002 part, 0.004 part, 0.01 part, 0.02 part, 0.03 part, 0.04 part, 0.045 part, or the like.

The complexing agent is 1-10 parts, for example, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts or 9 parts, etc.

The corrosion inhibitor is 0.001-0.5 part, for example, 0.002 part, 0.004 part, 0.006 part, 0.008 part, 0.01 part, 0.02 part, 0.03 part, 0.04 part, 0.1 part, 0.2 part, 0.3 part, 0.4 part or 0.45 part, etc.

Preferably, H in the sulfuric acid ₂ SO ₄ The mass percentage of (C) is 40-60%, for example, 45%, 50% or 55%.

Preferably, H in the hydrogen peroxide solution ₂ O ₂ The mass percentage of (C) is 40-60%, for example, 45%, 50% or 55%.

Other specific point values in the above numerical ranges are selectable, and will not be described in detail here.

Preferably, the hydrogen peroxide stabilizer comprises 2-amino-2-methyl-1-propanol and/or n-propanol.

Preferably, the organic acid has a structure as shown in formula I:

wherein R is selected from any one of C1-C6 (for example, C2, C3, C4 or C5) straight-chain or branched alkylene and phenylene.

Preferably, the organic acid comprises any one or a combination of at least two of thioglycolic acid, mercaptopropionic acid or 2-mercaptopropionic acid.

Preferably, the amino acid compound comprises methionine, cystine or

Any one or a combination of at least two of the following;

wherein R is ₁ Any one selected from H, methyl or acetyl;

R ₂ selected from S, SO or SO ₂ Any one of them;

R ₃ any one selected from H, acetyl, allyl, C1-C6 (which may be C2, C3, C4 or C5, for example) straight or branched alkyl, C3-C5 (which may be C3, C4 or C5, for example) heteroaryl, substituted or unsubstituted C6-C12 (which may be C7, C8, C9, C10 or C11, for example) aryl, substituted or unsubstituted C7-C12 (which may be C8, C9, C10 or C11, for example) alkylaryl;

the substituted substituents are each independently selected from any one of methyl, ethyl or methoxy.

Preferably, the amino acid compound comprises any one or a combination of at least two of methionine, cystine, D-cysteine, L-cysteine, N-acetylcysteine, amide S-benzylcysteine, S-allyl-L-cysteine, S-sulfocysteine, S-methyl-L-cysteine sulfoxide, S-methyl-L-cysteine, S-carboxymethyl-L-cysteine, S- (4-methylbenzyl) -L-cysteine, S-benzyl-L-cysteine sulfone, S-allyl-L-cysteine, S- (2-carboxyethyl) -L-cysteine, N-acetyl-S-methyl-L-cysteine, S- (2-thiazolyl) -L-cysteine or S- (3-carboxypropyl) -L-cysteine.

Preferably, the noble metal ion in the noble metal salt comprises Ag ⁺ 、Pd ²⁺ 、Au ³⁺ 、Pt ⁴⁺ Or Ru (Rust) ³⁺ Any one or a combination of at least two of these.

Preferably, the mass ratio of the amino acid compound to the noble metal salt is (5-200): 1, for example, 10:1, 20:1, 30:1, 40:1, 50:1, 80:1, 100:1, 120:1, 140:1, 160:1, 180:1, or the like.

Preferably, the complexing agent comprises any one or a combination of at least two of ethylenediamine tetramethylene sodium phosphate, diethylenetriamine pentamethylenephosphonate or aminotrimethylene phosphonic acid.

Preferably, the corrosion inhibitor comprises any one or a combination of at least two of 2-mercaptothiazole, 2- (benzyloxy) -1-methylpyridine-1-trifluoromethanesulfonate, N-butylpyridine hexafluorophosphate, 2-aminothiazole or polyethyleneimine.

Preferably, the molecular weight of the polyethyleneimine is 600-72000, and may be 700, 800, 900, 1000, 2000, 3000, 4000, 8000, 10000, 20000, 30000, 40000, 50000, 60000 or 70000, for example.

Preferably, when the corrosion inhibitor is polyethyleneimine, the amount is 0.001 to 0.05 part, for example, 0.002, 0.004, 0.006, 0.008, 0.01, 0.02, 0.03 or 0.04 part, etc.

In a second aspect, the present invention provides a method for preparing the etching solution according to the first aspect, the method comprising: and uniformly mixing the sulfuric acid, the hydrogen peroxide stabilizer, the organic acid, the amino acid compound, the noble metal salt, the complexing agent, the corrosion inhibitor and the water to obtain the etching liquid medicine.

In a third aspect, the present invention provides the use of an etching solution according to the first aspect for etching a copper layer of a circuit board.

Preferably, the method for etching a copper layer of a circuit board comprises the following steps: spraying the etching liquid on the circuit board for etching or soaking the circuit board in the etching liquid for etching.

Preferably, the temperature of the etching is 25-35 ℃, for example, 26 ℃, 28 ℃, 30 ℃, 32 ℃, 34 ℃ or the like.

Compared with the prior art, the invention has the following beneficial effects:

the etching water provided by the invention can obviously reduce the etching rate ratio of electroplated copper to electrolytic copper, reduce the copper loss of a circuit while removing bottom copper, and optimize the line type of the circuit, the line width of the etched circuit and the line height to meet the requirements. The hydrogen peroxide stabilizer and the corrosion inhibitor are added, so that the etching rate can be effectively controlled, and the rapid reduction of the etching rate caused by the decomposition of hydrogen peroxide in the etching process is avoided, and the etching effect is influenced; the organic acid contains sulfhydryl, the amino acid compound contains S, sulfonyl and sulfoxide groups, insoluble complex can be formed with noble metal ions to be adsorbed on the copper surface, and in the etching process, a spraying mode is adopted, and complex films on the surfaces of the bottom copper and the copper circuit are easily washed away by liquid medicine under the action of pressure, so that the etching in the vertical direction can be normally carried out, the complex adsorbed on the side of the copper circuit is not easily broken, and the complex acts as a revetment agent to effectively reduce the side etching rate and avoid line thinning; meanwhile, in the etching process, the insoluble complex is distributed in a gradient way on the side edge due to the reason of liquid medicine exchange, namely, the uppermost end is adsorbed more, the etching rate is lowest, the bottom end is adsorbed less, the etching rate is fastest, and the section of a circuit before etching is generally narrow at the top and wide at the bottom, so that the line width difference between the top and the bottom of the circuit can be reduced after etching, and the line type of the circuit is optimized; the corrosion inhibitor can be chemically adsorbed at the corner of the circuit, so that the radian of the circuit is reduced; complexing agentCan complex Cu ²⁺ Maintaining Cu in etching liquid ²⁺ The concentration is stable, the etching rate is stable, the copper capacity is increased, the groove changing frequency is reduced, and the sewage discharge is reduced. In conclusion, the etching liquid obtained by adopting the technical scheme of the invention can be used for processing the circuit board with dense fine lines, and has the characteristics of no residual copper of the bottom copper after etching, no undercut of the line, square line, small side etching and the like.

Drawings

FIG. 1 is a schematic diagram of a slice measurement method;

FIG. 2 is a diagram of the copper residue of the etching solution prepared in example 1 after etching;

FIG. 3 is a graph of copper residue at the bottom of the etching solution prepared in comparative example 2 after etching;

FIG. 4 is a view of an untreated test board circuit slice;

FIG. 5 is a circuit slice diagram of the test board after etching with the etchant prepared in example 3;

FIG. 6 is a circuit slice diagram of the test board after etching with the etchant prepared in example 5;

FIG. 7 is a circuit slice diagram of the test board after etching with the etchant prepared in example 7;

FIG. 8 is a circuit slice diagram of the test board after etching with the etchant prepared in example 8;

FIG. 9 is a circuit slice diagram of the test board after etching with the etchant prepared in example 10;

FIG. 10 is a circuit slice diagram of a test board after etching with the etching solution prepared in comparative example 1;

FIG. 11 is a circuit slice diagram of a test board after etching with the etching solution prepared in comparative example 3.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

The terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

"optional" or "any" means that the subsequently described event or event may or may not occur, and that the description includes both cases where the event occurs and cases where the event does not.

The indefinite articles "a" and "an" preceding an element or component of the invention are not limited to the requirement (i.e. the number of occurrences) of the element or component. Thus, the use of "a" or "an" should be interpreted as including one or at least one, and the singular reference of an element or component includes the plural reference unless the amount clearly dictates otherwise.

The description of the terms "one embodiment," "some embodiments," "exemplarily," "specific examples," or "some examples," etc., herein described means that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this document, the schematic representations of the above terms are not necessarily for the same embodiment or example.

Example 1

The embodiment provides an etching liquid, which comprises the following components in parts by weight:

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of N-propanol, 1 part of 2-mercaptopropionic acid, 0.02 part of N-acetyl-L-cysteine and AgNO ₃ 0.001 part of diethylenetriamine penta (methylene phosphonic acid) sodium 5 parts and 0.005 part of polyethyleneimine.

The preparation method of the etching liquid comprises the following steps: and uniformly mixing all the components according to the formula amount to obtain the etching liquid medicine.

Example 2

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of N-propanol, 1 part of 2-mercaptopropionic acid and N-ethylacyl-L-cysteine 0.02 parts, pdSO ₄ 0.001 part of ethylenediamine tetramethylene sodium phosphate 1 part and polyethyleneimine 0.01 part.

Example 3

100 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 10 parts of 2-amino-2-methyl-1-propanol, 2 parts of 2-mercaptopropionic acid, 0.005 part of DL cysteine and AgNO ₃ 0.001 part of aminotrimethylene phosphonic acid 5 parts and 2-aminothiazole 0.2 parts.

Example 4

100 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 10 parts of 2-amino-2-methyl-1-propanol, 2 parts of 2-mercaptopropionic acid, 0.01 part of DL cysteine and AgNO ₃ 0.001 part of aminotrimethylene phosphonic acid 5 parts and 2-aminothiazole 0.2 parts.

Example 5

100 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 10 parts of 2-amino-2-methyl-1-propanol, 2 parts of 2-mercaptopropionic acid, 0.05 part of DL cysteine and AgNO ₃ 0.001 part of aminotrimethylene phosphonic acid 5 parts and 2-aminothiazole 0.2 parts.

Example 6

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 10 parts of n-propanol, 2 parts of 2-mercaptopropionic acid, 0.2 part of S-benzyl-L-cysteine and AgNO ₃ 0.001 part of aminotrimethylene phosphonic acid 5 parts and 2-aminothiazole 0.1 part.

Example 7

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 10 parts of n-propanol, 2 parts of 2-mercaptopropionic acid, 0.2 part of S-benzyl-L-cysteine and AgNO ₃ 0.001 part of aminotrimethylene phosphonic acid 5 parts and 1 part of N-butylpyridine hexafluorophosphate.

Example 8

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of N-propanol, 1 part of propionic acid, 0.02 part of N-acetyl-L-cysteine, 0.001 part of AgNO3, 5 parts of diethylenetriamine penta-methylene phosphonate and 0.005 part of polyethyleneimine.

Example 9

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of N-propanol, 1 part of 2-mercaptopropane, 0.02 part of N-acetyl-L-cysteine and AgNO ₃ 0.001 part of diethylenetriamine pentamethylene phosphonate, 5 parts of polyethyleneimine and 0.005 part of polyethyleneimine.

Example 10

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of N-propanol, 1 part of 2-mercaptopropionic acid, 0.02 part of N-acetyl-L-alanine and AgNO ₃ 0.001 part of diethylenetriamine pentamethylene phosphonate, 5 parts of polyethyleneimine and 0.005 part of polyethyleneimine.

Comparative example 1

The comparative example provides an etching liquid, which comprises the following components in parts by weight:

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of N-propanol, 0.02 part of N-acetyl-L-cysteine and AgNO ₃ 0.001 part of diethylenetriamine penta (methylene phosphonic acid) sodium 5 parts and 0.005 part of polyethyleneimine.

Comparative example 2

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of n-propanol, 1 part of 2-mercaptopropionic acid and AgNO ₃ 0.001 part of diethylenetriamine penta (methylene phosphonic acid) sodium 5 parts and 0.005 part of polyethyleneimine.

Comparative example 3

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of N-propanol, 1 part of 2-mercaptopropionic acid, 0.02 part of N-acetyl-L-cysteine, 5 parts of diethylenetriamine penta (methylene phosphonic acid) sodium salt and 0.005 part of polyethyleneimine.

Comparative example 4

120 parts of 50% sulfuric acid, 60 parts of 50% hydrogen peroxide, 15 parts of N-propanol, 1 part of 2-mercaptopropionic acid, 0.02 part of N-acetyl-L-cysteine and AgNO ₃ 0.001 part of diethylenetriamine penta (methylene phosphonic acid) sodium 5 parts.

Test case

Test material: test boards (Guangzhou City and circuit board Co., ltd., S1141,0.5 OZ) were used and were manufactured by the modified semi-additive method (mSAP), and the test board parameters are shown in Table 1. In the spray test process, the etching solution prepared in examples 1-10 and comparative examples 1-4 had a volume of 5L, a temperature of 30deg.C, and a spray pressure of 1kg/cm ² The linear speed of the spraying machine is 1m/min, and the effective spraying length is 50cm.

1. Etch rate determination: taking 1 piece of 5 cm-10 cm copper-clad plate (S1141, 0.5OZ, manufactured by Guangzhou city and circuit board Co., ltd.) and spraying the etching liquid medicine prepared in examples 1-10 and comparative examples 1-4 in a spraying machine for 1min, recording the quality of the copper-clad plate before and after spraying, wherein the etching rate calculating method is specifically shown in formula 1:

formula 1: etch rate (μm/min) = (m 1-m 2)/(2×s×ρ) ×10000

Wherein m1 and m2 are respectively the quality of the copper-clad plate before and after treatment; ρ is the density of copper, 8.96g/cm is taken ³ The method comprises the steps of carrying out a first treatment on the surface of the S is the area of the processed copper-clad plate.

The etch rate test results are shown in table 1.

2. And (3) testing residual copper: the etching liquid medicines prepared in examples 1-10 and comparative examples 1-4 are respectively sprayed on a test board, the etching amount of the test board is 3.5 mu m, the test board is placed under a microscope (Kidney VK-X3000) after the treatment is finished to observe the residual condition of copper at the bottom of a dense fine circuit area, the test results are shown in the table 1, wherein the "no residue" indicates: under the condition of 2400 times of microscope, no residual copper points are seen; "small amount of residue" means: under the condition of 2400 times of a microscope, the number of copper points is 5-20; "more residual" means: under the condition that the residual rate of copper under the bottom is 2400 times of a microscope, the number of copper points is 21-100; "substantial residue" means: the copper dot number is more than 100 under the condition that the copper bottom residual rate is 2400 times of a microscope.

Illustratively, the graph of copper residue after etching with the etching solution prepared in example 1 is shown in fig. 1, and the graph of copper residue after etching with the etching solution prepared in comparative example 2 is shown in fig. 2.

As shown in the figure, the bottom copper in the example 1 is etched cleanly, no spots are found under a microscope, and more spots exist in the residual copper graph of the comparative example 2, which indicates that the bottom copper has obvious residual phenomenon and more residues exist.

3. Post etch line parameters: the etching liquid prepared in examples 1-10 and comparative examples 1-4 is sprayed and tested respectively, the etching amount of the test piece is 3.5 μm, relevant parameters of dense fine lines are observed through slicing, chemical nickel plating treatment is needed to be carried out on the test piece before slicing, each parameter of the lines is recorded under a microscope (Olin Bass, U25-LBA) and the magnification is 500 times, the slicing measurement method is shown in figure 3, L1 and L2 are the line width on the lines and the line width under the lines respectively, L3 is the line distance, H1 is the line height, H2 is the line top radian height, the line radian proportion is obtained through H2/(H1-H2) calculation, and the measured line parameter results are shown in table 1.

Untreated test board line slices are shown in FIG. 4; illustratively, the test board circuit slices after etching with the etching solution prepared in examples 3, 5, 7, 8, 10 are shown in fig. 5-9, and the test board circuit slices after etching with the etching solution prepared in comparative examples 1 and 3 are shown in fig. 10-11.

TABLE 1

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From the table data, the circuit parameters after treatment with the etching solutions prepared in examples 1-10 were significantly better than those of the comparative examples. From the side etching point of view, the line widths after the etching solution treatment of examples 1 to 10 fluctuated in the range of 24.47 μm to 26.08 μm, and the line widths after the etching solution treatment of comparative examples 1 to 4 were only 22.22 μm to 24.81 μm, so that the line width side etching amount after the etching solution treatment of examples 1 to 10 was reduced by about 2 μm as a whole. From the line linetype point of view, the line width difference after the etching solution treatment prepared in examples 1 to 10 is only 0.22 μm to 0.69 μm, the line radian ratio is 14.7% to 16.9%, and the line width difference after the etching solution treatment prepared in comparative examples 1 to 4 is 1.08 μm to 2.59 μm, the line radian ratio is 18.5% to 19.3%, and the values of both are obviously higher, which indicates that the line linetype after the treatment of examples is better; from the standpoint of etching dryness of the base copper, the test boards prepared in examples 1 to 10 after the etching solution treatment had no base copper residue under the same etching amount, while comparative examples 1 to 4 had base copper residues in different proportions. In addition, as shown in examples 3 to 5, the etching rate of the etching solution is reduced with the increase of the amino acid content in the etching solution, but the amount of the side etching after the line etching is reduced, the line width is increased, and the line shape is more square; as is clear from examples 3, 8 and 10, when the organic acid does not contain a mercapto group, the line width difference and the radian ratio after etching increase and the line shape slightly deteriorates when the amino acid does not contain sulfur.

The applicant states that the process of the invention is illustrated by the above examples, but the invention is not limited to, i.e. does not mean that the invention must be carried out in dependence on the above process steps. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of selected raw materials, addition of auxiliary components, selection of specific modes, etc. fall within the scope of the present invention and the scope of disclosure.

Claims

1. The etching liquid is characterized by comprising the following components in parts by weight:

2. the etching solution of claim 1, wherein H in sulfuric acid ₂ SO ₄ The mass percentage of (2) is 40-60%;

preferably, H in the hydrogen peroxide solution ₂ O ₂ The mass percentage of the (C) is 40-60%.

3. Etching solution according to claim 1 or 2, characterized in that the hydrogen peroxide stabilizer comprises 2-amino-2-methyl-1-propanol and/or n-propanol.

4. The etching solution of any one of claims 1-3, wherein the organic acid has a structure according to formula I:

wherein R is selected from any one of C1-C6 straight-chain or branched-chain alkylene and phenylene;

5. The etching solution of any of claims 1-4, wherein the amino acid compound comprises methionine, cystine, or

Any one or a combination of at least two of the following;

wherein R is ₁ Any one selected from H, methyl or acetyl;

R ₂ selected from S, SO or SO ₂ Any one of them;

R ₃ selected from H, acetyl, allyl, C1-C6 straight or branched alkyl, C3-C5 heteroaryl, substituted or unsubstitutedAny one of C6-C12 aryl, substituted or unsubstituted C7-C12 alkylaryl;

each of the substituted substituents is independently selected from any one of methyl, ethyl or methoxy;

6. The etching solution of any of claims 1-5, wherein the noble metal ion in the noble metal salt comprises Ag ⁺ 、Pd ²⁺ 、Au ³⁺ 、Pt ⁴⁺ Or Ru (Rust) ³⁺ Any one or a combination of at least two of the following;

preferably, the mass ratio of the amino acid compound to the noble metal salt is (5-200): 1.

7. The etching solution of any of claims 1-6, wherein the complexing agent comprises any one or a combination of at least two of ethylenediamine tetramethylene sodium phosphate, diethylenetriamine pentamethylenephosphonate, or aminotrimethylene phosphonic acid.

8. The etching solution of any of claims 1-7, wherein the corrosion inhibitor comprises any one or a combination of at least two of 2-mercaptothiazole, 2- (benzyloxy) -1-methylpyridine-1-trifluoromethanesulfonate, N-butylpyridinium hexafluorophosphate, 2-aminothiazole, or polyethyleneimine.

9. A method of preparing the etching solution according to any one of claims 1 to 8, comprising: and uniformly mixing the sulfuric acid, the hydrogen peroxide stabilizer, the organic acid, the amino acid compound, the noble metal salt, the complexing agent, the corrosion inhibitor and the water to obtain the etching liquid medicine.

10. Use of the etching solution according to any one of claims 1 to 8 for etching copper layers of circuit boards;

preferably, the method for etching a copper layer of a circuit board comprises the following steps: spraying the etching liquid on the circuit board for etching or soaking the circuit board in the etching liquid for etching;

preferably, the temperature of the etching is 25-35 ℃.