Alkali-free system developing solution and developing method thereof

Abstract

The invention discloses an alkali-free system developing solution and a developing method thereof, and relates to the technical field of circuit board production. The alkali-free system developing solution comprises the following components in mass concentration: 3.0-6.0% of a developing agent; 1.0%-3.0% of an accelerator; 0.5%-2.0% of a wetting agent; 1.0%-3.0% of a permeation aid; and 0.2-1.0% of a stabilizing agent. The alkali-free system developing solution has the core advantages of being free of alkali corrosion, low in foam, rapid in defoaming, fine in developing, stable in performance, excellent in plating resistance and the like, is particularly suitable for developing lines with the line width and the line spacing of 5 micrometers, and can remarkably improve the definition and the integrity of patterns, effectively reduce developing residues and assist high-precision line forming.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit board production, and particularly to an alkali-free system developer and a developing method thereof. Background Art

[0002] In the fields of semiconductor manufacturing, flat panel display, and printed circuit board (PCB), as the core process of graphic transfer, the performance of the developer directly determines the quality and yield of the final product. Taking the PCB developing process as an example, its complete process includes: substrate cleaning (removing oxides and contaminants) → coating photoresist (dry film / liquid) → pre-baking (90 - 110 °C) → exposure → development → deionized water rinsing → drying → post-treatment (etching / electroplating).

[0003] Traditional PCB developers have multiple bottlenecks in practical applications: Firstly, there are precision defects in the process. The developing speed is difficult to accurately control. If it is too fast, it is easy to cause poor uniformity and rough circuit edges, unable to meet the requirements of high-precision graphic transfer; if it is too slow, problems such as incomplete development and residual glue will occur. Secondly, there are challenges in the stability of the product. When the developer is recycled, a large number of bubbles are easily generated, interfering with the stability of the developing process and shortening the service life of the solution. Finally, there is also severe environmental protection pressure. Some developers are highly corrosive, and the supporting wastewater treatment cost is high and difficult, making it difficult to meet the current environmental protection requirements of green manufacturing.

[0004] Facing the trend of the development of electronic products towards high density and miniaturization, the technological iteration of PCB developers shows four major directions: First, high precision, which needs to adapt to the transfer of finer circuit patterns, improve resolution and developing uniformity, and ensure the integrity of complex graphics; second, green environmental protection, by reducing toxicity, corrosivity, and designing biodegradable formulations, simplifying the wastewater treatment process, and at the same time increasing the recycling rate of the developer to reduce resource consumption; third, high efficiency and stability, developing long-cycle stable formulations to maintain the consistency of developing effects under different production conditions such as temperature and pressure, and at the same time increasing the developing speed to adapt to the requirements of large-scale mass production; fourth, material process compatibility, optimizing the developer composition to enhance adaptability for new processes such as new photoresists and laser direct imaging.

[0005] An alkali-free developer is a developer that does not contain traditional alkaline components. It usually uses other types of compounds to achieve the developing function. The alkali-free developer has the following advantages: First, the alkali-free developer avoids environmental pollution caused by alkaline substances. Its wastewater treatment is relatively simple, reducing the environmental protection pressure. Second, the alkali-free developer usually has low toxicity and corrosiveness, and the safety risk to operators is relatively small. In addition, due to the absence of strong alkali, the alkali-free developer has less corrosiveness to developing equipment, can extend the service life of the equipment, and reduce the equipment maintenance cost. Third, in some special PCB manufacturing processes, such as for certain sensitive materials or high-precision lithography processes, the alkali-free developer can provide better developing effects, avoid the influence of alkaline substances on material properties, and help improve the yield and performance of products.

[0006] There are currently some technical solutions for developers introduced. CN109375482A proposes a PCB developer and its preparation method. The developer contains 5-20 parts of diethylene glycol amine, 2-6 parts of citric acid, 0.5-5 parts of polyether amine, 3-10 parts of hexanediol, and 60-80 parts of water, which can reduce the defective developing rate and increase the usage time of the developer, and there is no need to change the tank for a long time. CN113419410A discloses an environmentally friendly developer and its preparation method. Its composition is: 10-20% of ethylene glycol, 8-10% of sodium carbonate, 12-15% of tetramethylammonium hydroxide, 0.5-1.5% of p-phenylenediamine, 2-5% of anti-aging agent, and the balance is water, which can prevent the developer from aging, ensure the service life of the developer and does not affect the usage effect. CN115657429B discloses a highly efficient environmentally friendly developer for PCB boards. Its composition is: 60-100 parts of organic base composition, 30-80 parts of co-solvent, 30-70 parts of defoamer, 40-70 parts of surfactant, 20-50 parts of antioxidant, 15-45 parts of penetrant, 30-50 parts of buffer, 10-20 parts of inhibitor, and the balance is water, which can improve the antioxidant capacity of the developer and PCB boards and ensure the stability during the use of the developer.

[0007] Existing developers generally meet the requirements of conventional PCB production processes. Traditional developers often utilize alkaline systems (such as sodium carbonate and potassium carbonate). While these solutions effectively dissolve the photosensitive resin in unexposed areas, their technical limitations are becoming a bottleneck restricting industry development. On the one hand, alkaline environments can corrode substrate materials (such as metal layers like aluminum and copper, as well as sensitive photoresists), causing damage to the metal layers and distortion of the photoresist pattern. Furthermore, alkaline developers are prone to uneven development and residue when processing chemically amplified photoresists and high-aspect-ratio structures, making them difficult to meet the demands of high-precision photolithography processes. This is particularly true in emerging fields like flexible electronics and microelectromechanical systems, where flexible substrate materials (such as polyimide and polyester film) are extremely sensitive to alkaline environments. The corrosive nature of traditional developers can damage the substrate structure, hindering the development of related industries. Furthermore, the wastewater generated by alkaline developers is difficult and costly to dispose of, which aligns with current trends in green manufacturing and environmentally friendly production.

[0008] Therefore, developing an alkali-free developer that maintains high development performance while reducing the risk of corrosion to the substrate and photoresist, while also meeting environmental requirements, has become a pressing technical challenge in the current photolithography industry. The semiconductor and printing industries are in urgent need of "green chemical processes," requiring developers to possess the following characteristics: first, environmental friendliness, including components free of strong alkali and low toxicity; second, high-precision compatibility, adaptability to photolithography development processes with line widths / line spacings of ≤5μm; and third, long-term stability, avoiding component decomposition or precipitation to reduce the risk of production downtime. Summary of the Invention

[0009] To address the shortcomings of the prior art, the present invention provides an alkali-free developer and a development method thereof, which can be applied to the development process of PCBs. The alkali-free developer contains active ingredients such as a developer, an accelerator, a wetting agent, a penetration aid, and a stabilizer. The developer is a class of compounds containing functional groups such as sulfonyl and hydroxyl groups, and primarily achieves development through hydrogen bond formation, redox activity, and polarity regulation. The accelerator increases the development rate by accelerating the hydrolysis or saponification reaction of soluble substances in the photoresist. The wetting agent accelerates the developer's penetration into the pores of the dry film, improving penetration efficiency. The protective agent prevents the developer from being oxidized, extending the service life of the developer. The penetration aid is a key auxiliary agent that reduces interfacial tension through surface activity, enhances the developer's penetration ability, and optimizes dissolution kinetics, thereby achieving high-precision pattern transfer. The stabilizer is primarily used to maintain the stability of the developer system, extending the developer's service life.

[0010] Specifically, the present invention provides an alkali-free developer comprising the following components in the following mass concentrations: Developer 3.0-6.0%; Accelerator 1.0-3.0%; Wetting agent 0.5-2.0%; Penetrant 1.0 - 3.0%; Stabilizer 0.2 - 1.0%; The developer is selected from one or a mixture of more than one of 1-(phenylsulfonyl)cyclopropan-1-ol (CAS No.: 1006613-82-6), 1-(methylsulfonyl)piperidin-4-ol (CAS No.: 141482-19-1), 3-(methylsulfonyl)benzyl alcohol (CAS No.: 220798-39-0); The accelerator is selected from one or a mixture of more than one of 1,3-bis(hydroxymethyl)-5,5-dimethylimidazoline-2,4-dione (CAS No.: 6440-58-0), imidazoline-2,4-dione (CAS No.: 461-72-3), 3-methylimidazolidine-2,4-dione (CAS No.: 6843-45-4); The wetting agent is selected from one or a mixture of more than one of 2,7-dihydroxynaphthalene (CAS No.: 582-17-2), 2,3-dihydroxynaphthalene (CAS No.: 92-44-4), 2,6-dihydroxynaphthalene (CAS No.: 581-43-1); The penetrant is selected from one or a mixture of more than one of 6-azidohexan-1-ol (CAS No.: 146292-90-2), 3-azido-1-propanol (CAS No.: 72320-38-8), 4-azidobenzyl alcohol (CAS No.: 31499-54-4); The stabilizer is selected from one or a mixture of more than one of methylpyridapho (CAS No.: 35575-96-3), chlorpyrifos (CAS No.: 42509-80-8), triazophos (CAS No.: 24017-47-8).

[0011] Preferably, the alkali-free system developer is composed of the following components in mass concentration: Developer 3.0 - 6.0%; Accelerator 1.0 - 3.0%; Wetting agent 0.5 - 2.0%; Penetrant 1.0 - 3.0%; Stabilizer 0.2 - 1.0%; The balance is water.

[0012] More preferably, the alkali-free system developer is composed of the following components in mass concentration: Developer 4.5%; Accelerator 2.0%; Wetting agent 1.0%; Penetrant 2.0%; Stabilizer 0.5%; The remainder is water.

[0013] The preparation method of the above-mentioned alkali-free system developer of the present invention is as follows: Weigh the developer, accelerator, wetting agent, penetration aid, and stabilizer according to the required mass concentration, add them to water, and mix evenly at room temperature to obtain the developer.

[0014] The above-mentioned alkali-free system developer of the present invention is used for the circuit development of circuit boards with a line width and line pitch of 5 μm.

[0015] The present invention also provides a developing method, which includes the following developing section steps: Spraying the circuit board to be developed with the above-mentioned alkali-free system developer with a mass concentration of 2-5% to make the circuit pattern appear on the circuit board.

[0016] Preferably, in the above-mentioned developing section steps, the spraying pressure is 1.5±0.5 kg / cm 2 , and the spraying time is 15±2 s.

[0017] Furthermore, in the above-mentioned developing method, a pre-soaking section step is also included before the developing section: Immersing the exposed circuit board in the pre-soaking section solution for 15±2 s; The pre-soaking section solution consists of the above-mentioned alkali-free system developer with a mass concentration of 0.8-1.2% and the remainder water. The function of the pre-soaking section is pre-soaking and swelling, which helps to quickly remove the dry film in the developing section.

[0018] In some specific embodiments, the developing method of the present invention sequentially includes the following pre-soaking section and developing section steps: Pre-soaking section: Immersing the exposed circuit board in the pre-soaking section solution for 15±2 s; The pre-soaking section solution consists of the above-mentioned alkali-free system developer with a mass concentration of 1.0% and the remainder water; Developing section: Spraying the pre-soaked circuit board with the above-mentioned alkali-free system developer with a mass concentration of 3%, and the spraying pressure is 1.5±0.5 kg / cm 2 , and the spraying time is 15±2 s.

[0019] The alkali-free system developer of the present invention has core advantages such as alkali-free corrosion, low foaming, rapid defoaming, fine development, stable performance, and excellent plating resistance. It is particularly suitable for the circuit development of line widths and line pitches of 5 μm level, can significantly improve the graphic clarity and integrity, effectively reduce the development residue, and help the formation of high-precision circuits. The alkali-free system developer has high stability, can reduce the defective rate of fine circuit development, and improve the overall manufacturing efficiency. Description of the Drawings

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0021] Figure 1 It is the developed pattern observed by an optical microscope after development in Example 1; Figure 2 It is the developed pattern observed by an optical microscope after development in Comparative Example 11. Specific Embodiments

[0022] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0023] It should be noted that the contents or concentrations described in the following examples / comparative examples are all mass concentrations.

[0024] The preparation methods of the alkali-free system developers in the following Examples 1-5 are as follows: According to the formulations of Examples 1-5, the developer, accelerator, wetting agent, penetration aid, stabilizer, and the remaining water are sequentially weighed and added to the reaction kettle, and stirred and mixed at room temperature for 30 minutes to obtain the alkali-free system developers corresponding to the examples. The obtained alkali-free system developers are sealed and stored for later use.

[0025] Example 1: The alkali-free system developer of this example is composed of the following components by mass concentration: The content of the developer is 4.5%, specifically 1-(phenylsulfonyl)cyclopropan-1-ol; The content of the accelerator is 2.0%, specifically 1,3-bis(hydroxymethyl)-5,5-dimethylimidazoline-2,4-dione; The content of the wetting agent is 1.0%, specifically 2,7-dihydroxynaphthalene; The content of the penetration aid is 2.0%, specifically 6-azidohexan-1-ol; The content of the stabilizer is 0.5%, specifically pirimiphos-methyl; The balance is water.

[0026] Example 2: The alkali-free system developer of this example is composed of the following components by mass concentration: The content of the developer is 4.5%, specifically 1-(methylsulfonyl)piperidin-4-ol; The accelerator content is 2.0%, specifically imidazoline-2,4-dione; The wetting agent content is 1.0%, specifically 2,3-dihydroxynaphthalene; The penetration enhancer content is 2.0%, specifically 3-azido-1-propanol; The stabilizer content is 0.5%, specifically chlorpyrifos-methyl; The balance is water.

[0027] Example 3: The alkali-free system developer of this example is composed of components with the following mass concentrations: The developer content is 4.5%, specifically 3-(methylsulfonyl)benzyl alcohol; The accelerator content is 2.0%, specifically 3-methylimidazolidine-2,4-dione; The wetting agent content is 1.0%, specifically 2,6-dihydroxynaphthalene; The penetration enhancer content is 2.0%, specifically 4-azidobenzyl alcohol; The stabilizer content is 0.5%, specifically triazophos; The balance is water.

[0028] Example 4: The alkali-free system developer of this example is composed of components with the following mass concentrations: The developer content is 3.0%, specifically 1-(phenylsulfonyl)cyclopropan-1-ol; The accelerator content is 1.0%, specifically 1,3-bis(hydroxymethyl)-5,5-dimethylimidazoline-2,4-dione; The wetting agent content is 0.5%, specifically 2,7-dihydroxynaphthalene; The penetration enhancer content is 1.0%, specifically 6-azidohexan-1-ol; The stabilizer content is 0.2%, specifically pirimiphos-methyl; The balance is water.

[0029] Example 5: The alkali-free system developer of this example is composed of components with the following mass concentrations: The developer content is 6.0, specifically 1-(phenylsulfonyl)cyclopropan-1-ol; The accelerator content is 3.0%, specifically 1,3-bis(hydroxymethyl)-5,5-dimethylimidazoline-2,4-dione; The wetting agent content is 2.0%, specifically 2,7-dihydroxynaphthalene; The penetration enhancer content is 3.0%, specifically 6-azidohexan-1-ol; The stabilizer content is 1.0%, specifically pirimiphos-methyl; The remainder is water.

[0030] Comparative Example 1 Compared with Example 1, the difference in Comparative Example 1 is only that the developer is not contained in the components.

[0031] Comparative Example 2 Compared with Example 1, the difference in Comparative Example 2 is only that the accelerator is not contained in the components.

[0032] Comparative Example 3 Compared with Example 1, the difference in Comparative Example 3 is only that the wetting agent is not contained in the components.

[0033] Comparative Example 4 Compared with Example 1, the difference in Comparative Example 4 is only that the penetration aid is not contained in the components.

[0034] Comparative Example 5 Compared with Example 1, the difference in Comparative Example 5 is only that the stabilizer is not contained in the components.

[0035] Comparative Example 6 Compared with Example 1, the difference in Comparative Example 6 is only that the concentration of the developer in the components is 12.0%.

[0036] Comparative Example 7 Compared with Example 1, the difference in Comparative Example 7 is only that the concentration of the accelerator in the components is 6.0%.

[0037] Comparative Example 8 Compared with Example 1, the difference in Comparative Example 8 is only that the concentration of the wetting agent in the components is 4.0%.

[0038] Comparative Example 9 Compared with Example 1, the difference in Comparative Example 9 is only that the concentration of the penetration aid in the components is 6.0%.

[0039] Comparative Example 10 Compared with Example 1, the difference in Comparative Example 10 is only that the concentration of the stabilizer in the components is 2.0%.

[0040] Comparative Example 11 Use the developer described in the prior art CN109375482A. Specifically, its components include: 5% of diethylene glycol amine, 2% of citric acid, 0.5% of polyether amine, 3% of hexanediol, and the remainder is water.

[0041] Perform the following foam performance, development performance, stability performance, and anti-plating performance tests on the developers of the above examples / comparative examples. The specific test methods are as follows: 1) Foam performance: Take the developer of the example / comparative example, and add tap water to prepare a solution with a concentration of 0.6%; use an RM-2 digital Roe foam meter for testing, the test temperature is 25 °C, and avoid ventilation or vibration during the test to affect the foam stability. Record the initial foam height (unit: mm, denoted as H0) and the time for the foam to reduce to half of its height (T). Each sample is tested in parallel at least 3 times, and the average value is taken.

[0042] 2) Development performance: Use the developer of the example / comparative example for the development of an IC carrier with a 5-μm line width / line pitch according to the following development process; observe whether the pattern can be developed clearly, and use a SU1510 type scanning electron microscope to test the proportion of the dry film remaining on the surface of the circuit board after development, that is, the development residue rate. The development residue rate should be ≤0.5%. The specific development process is: degreasing → water washing → drying → film laminating → exposure → development → water washing → etching → water washing → film stripping → water washing → drying; among them, the developer of the example / comparative example is used for the development process, which is divided into: pre-soaking section → development section, two treatment sections: The process of the pre-soaking section is: This section is of the immersion type; the solution composition in the pre-soaking tank is 1.0% of the developer of the example / comparative example, and the balance is water; the pre-soaking temperature is 25 ± 1 °C, the length of the pre-soaking section is 0.5 m, and the linear speed is 2.0 ± 0.2 m / min. The process of the development section is: This section is of the spray type; the solution composition in the development tank is 3.0% of the developer of the example / comparative example, and the balance is tap water; the development temperature is 25 ± 1 °C, and the length of the development section is 0.5 m; the linear speed is 2.0 ± 0.2 m / min, and the pressure is 1.5 ± 0.5 kg / cm 2 ; 3) Stability performance: Take the developer of the example / comparative example and store it at 40 °C for 7 days, and observe the change in the surface tension of the solution on the first day and the seventh day; the test method for surface tension is the capillary rise method. Specifically, insert a clean capillary vertically into the developer of the example / comparative example. Due to the action of surface tension, the solution will rise to a certain height in the capillary; according to parameters such as the capillary radius, solution density, gravitational acceleration, and the height of the solution rising in the capillary, the surface tension of the solution can be calculated using relevant formulas. The calculation formula is ; where γ is the surface tension; r is the capillary radius; h is the height of the solution rising in the capillary; ρ is the density of the solution; g is the gravitational acceleration; θ is the contact angle; 4) Anti-plating performance: Apply the developer of the example / comparative example evenly on the test board, wash it with water and then perform electroplating, and observe the electroplating condition of the test board; it is required in the present invention that no electroplating solution penetrates into the non-patterned area (substrate) or under the photoresist, causing problems such as plating penetration.

[0043] The performance test results of the developers in Examples 1-5 and Comparative Examples 1-11 are shown in Table 1 as follows: Table 1 Performance Test Results of the Developer

[0044] The developed pattern observed by optical microscope after developing in Example 1 is as shown in Figure 1 ; The developed pattern observed by optical microscope after developing in Comparative Example 11 is as shown in Figure 2 .

[0045] It can be seen from the test results of Examples 1-5 in Table 1 that the foam height of the alkali-free system developer of the present invention is 2.0 - 2.5 mm, the time for half of the foam to disappear is 1.5 - 2.0 s, and the foam performance of the product is excellent; the development residue rate of the 5-μm line width and line pitch circuit board is 0.02 - 0.06%, and the development performance of the product is excellent; the surface tension of the product remains unchanged on the first day and the seventh day, and the surface tension is 14.2 - 14.7 mN / m, and the stability performance of the product is excellent; when the anti-plating test is carried out with the developer of the present invention, no plating penetration phenomenon occurs, and the anti-plating performance of the product is excellent. It shows that the alkali-free system developer of the present invention has the advantages of no alkali corrosion, less foam, rapid foam elimination, fine development, stable performance, excellent anti-plating effect, etc., and can be applied to the fine circuit development process with a 5-μm line width and line pitch. After development, the pattern is clear and complete, the development residue rate is low, which is beneficial to the high-precision forming of fine circuits, the stability performance of the product is good, the defective rate of fine circuit development can be reduced, and the manufacturing efficiency can be improved.

[0046] The differences between Comparative Examples 1-5 and Example 1 are that the single components of the developer, accelerator, wetting agent, penetration aid, and stabilizer are respectively missing. The test results show that the developer is an important component for development. When this component is missing, the development performance of the developer drops significantly, and the foam performance, stability performance, and anti-plating performance are all affected. The three components of accelerator, wetting agent, and penetration aid mainly provide auxiliary effects for the developer. When any one of these three components is missing, the performance of the developer will drop slightly. The stabilizer mainly plays a role in maintaining the stability of the developer effect. When this component is missing in the components, the stability performance of the product will drop significantly. Therefore, the excellent performance of the developer of the present invention is the result of the interaction of each component, and the lack of any component will affect the performance of the product.

[0047] The differences between Comparative Examples 6-10 and Example 1 are that in the developer of the alkali-free system of the present invention, the developer, accelerator, wetting agent, penetration aid, and stabilizer are respectively higher than the upper limit of the concentration of the present invention. The test results show that compared with Examples 1-5, too high concentrations of the developer, accelerator, wetting agent, penetration aid, and stabilizer will not affect the development performance, but too high concentrations will increase the cost of the chemical solution. Therefore, the concentrations of the components of the developer of the present invention should not be too high, and stable development effects of the chemical solution can be ensured within the concentration range defined by the present invention.

[0048] Comparative Example 11 uses the development solution of the prior art. The test results show that the developer of the present invention has a lower foam height, a faster defoaming time, a better development residue rate, a lower surface tension and stable performance, and a better anti-plating performance, and can be applied to the alkali-free development process of fine circuits.

[0049] In summary, the alkali-free system developer provided by the present invention has core advantages such as alkali-free corrosion, low foam, fast defoaming, fine development, stable performance, and excellent anti-plating performance. It is particularly suitable for the development of fine circuits with a line width and line pitch of 5 μm, can significantly improve the graphic clarity and integrity, effectively reduce the development residue, and help the formation of high-precision circuits. This product has high stability, can reduce the defective rate of fine circuit development, and improve the overall manufacturing efficiency.

[0050] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An alkali-free developing solution, characterized in that, Comprising components with the following mass concentrations: Developer 3.0 - 6.0%; Accelerator 1.0 - 3.0%; Wetting agent 0.5 - 2.0%; Penetration aid 1.0 - 3.0%; Stabilizer 0.2 - 1.0%; The developer is selected from one or a mixture of more than one of 1-(phenylsulfonyl)cyclopropan-1-ol, 1-(methylsulfonyl)piperidin-4-ol, 3-(methylsulfonyl)benzyl alcohol; The accelerator is selected from one or a mixture of more than one of 1,3-bis(hydroxymethyl)-5,5-dimethylimidazoline-2,4-dione, imidazoline-2,4-dione, 3-methylimidazolidine-2,4-dione; The wetting agent is selected from one or a mixture of more than one of 2,7-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene; The penetration aid is selected from one or a mixture of more than one of 6-azidohexan-1-ol, 3-azidopropan-1-ol, 4-azidobenzyl alcohol; The stabilizer is selected from one or a mixture of more than one of pirimiphos-methyl, isazofos, triazophos.

2. The alkali-free system developer according to claim 1, wherein, Composed of components with the following mass concentrations: Developer 3.0 - 6.0%; Accelerator 1.0 - 3.0%; Wetting agent 0.5 - 2.0%; Penetration aid 1.0 - 3.0%; Stabilizer 0.2 - 1.0%; The balance is water.

3. The alkali-free system developer according to claim 1, characterized in that Composed of components with the following mass concentrations: Developer 4.5%; Accelerator 2.0%; Wetting agent 1.0%; Penetration aid 2.0%; Stabilizer 0.5%; The balance is water.

4. The preparation method of the alkali-free system developer according to any one of claims 1-3, characterized in that, Weigh the developer, accelerator, wetting agent, penetration aid, and stabilizer according to the required formulated mass concentration, add them to water, and mix evenly at room temperature to obtain.

5. The alkali-free system developer according to any one of claims 1-3, characterized in that, For the circuit development of a circuit board with a 5μm line width and line pitch.

6. A developing method, characterized in that, Including the following steps in the development stage: Spray the circuit board to be developed with the alkali-free system developer solution described in any one of claims 1 - 3 with a mass concentration of 2 - 5% to make the circuit pattern appear on the circuit board.

7. The developing method according to claim 6, wherein In the developing section step, the spraying pressure is 1.5 ± 0.5 kg / cm 2 , and the spraying time is 15 ± 2 s.

8. The developing method according to claim 6, characterized in that, Before the development stage, it also includes the steps of the pre-soaking stage: Immerse the exposed circuit board in the pre-soaking stage medicine for 15 ± 2 s; The pre-soaking stage medicine is composed of the alkali-free system developer solution described in any one of claims 1 - 3 with a mass concentration of 0.8 - 1.2% and the balance water.

9. A developing method, characterized in that, Sequentially including the following steps of the pre-soaking stage and the development stage: Pre-soaking stage: Immerse the exposed circuit board in the pre-soaking stage medicine for 15 ± 2 s; The pre-soaking stage medicine is composed of the alkali-free system developer solution described in any one of claims 1 - 3 with a mass concentration of 1.0% and the balance water; Developing section: Spray the circuit board after pre-impregnation with the alkali-free system developer solution described in any one of claims 1-3 with a mass concentration of 3%, with a spray pressure of 1.5 ± 0.5 kg / cm 2 , and a spray time of 15 ± 2 s.

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