Semiconductor ceramic plate thin copper etching solution and preparation method thereof

Abstract

The invention discloses a semiconductor ceramic plate thin copper etching solution and a preparation method thereof.The etching solution is composed of sulfuric acid, sodium persulfate, a modified nitrogen heterocyclic accelerator, a surfactant, deionized water and other raw materials, under the synergistic effect of the modified nitrogen heterocyclic accelerator and other raw materials in the proportion, titanium metal is not corroded, and the etching effect is good. The etching effect is only formed on copper metal, and the etched ceramic substrate is small in line side etching and high in etching factor. Meanwhile, the etching solution is stable in etching rate, high in copper ion tolerance, small in consumption, long in service life and high in treatment capacity, and the etched copper surface is free of oxidation and dirt and is slightly red and bright in color.

Description

Technical Field

[0001] The invention relates to the technical field of surface treatment of ceramic substrates in the semiconductor industry, and more specifically to a semiconductor ceramic plate thin copper etching solution and a preparation method thereof. Background Art

[0002] In the field of PCB (printed circuit board) copper etching solutions, acidic etching solutions and alkaline etching solutions are mainly used. Acidic etching is negative etching, and the composition of the solution is generally sodium chlorate + additives + hydrochloric acid system, and the etching rate can reach: 30-50um / min. Alkaline etching is positive etching, and the composition of the solution is generally ammonium chloride + additives + ammonia system, and the etching rate can reach: 40-70um / min.

[0003] In the manufacturing process of ceramic substrates, after titanium metal is sputtered on the surface of the substrate, a thin copper substrate will be produced in the copper coating process of DPC and DBC manufacturing processes, and the thickness of the copper layer is generally 3-5um. In the later molding and manufacturing of the substrate, the copper layer and titanium layer need to be etched away to form a thicker circuit. The above acidic and alkaline etching solutions are completely inapplicable in the copper etching process of this substrate. The high etching rate can easily cause serious corrosion to the copper layer that needs to be retained on the substrate, which has a significant impact on the reliability of the substrate.

[0004] For copper thickness of 3-5um, the micro-etching solution of sulfuric acid + hydrogen peroxide + stabilizer system is the most suitable for etching this type of substrate. However, hydrogen peroxide will easily attack titanium metal. Although adding a passivation inhibitor can resist the corrosion of titanium metal by the solution, it will also inhibit the ability of hydrogen peroxide as an oxidant and reduce the performance of the solution, increase the amount of solution used, and some gains outweigh the losses. Therefore, this type of micro-etching solution is not applicable.

[0005] The micro-etching ability of sulfuric acid + persulfate system micro-etching solution is low and the life is short. Etching this type of plate will increase the application cost a lot, and it will also have a slight attack on titanium metal.

[0006] Therefore, it is urgent to develop a new thin copper etching solution to solve the above technical problems. Summary of the invention

[0007] The object of the present invention is to overcome the above-mentioned defects in the prior art and provide a semiconductor ceramic plate thin copper etching solution and a preparation method thereof.

[0008] To achieve the above object, the first aspect of the present invention provides a semiconductor ceramic plate thin copper etching solution, which is composed of the following raw materials in percentage by mass:

[0009]

[0010] Wherein, the chemical structural formula of the modified nitrogen heterocyclic accelerator is as follows:

[0011]

[0012] Preferably, the concentration of the sulfuric acid is 50 wt %.

[0013] Preferably, the concentration of the sodium persulfate is 99%.

[0014] Preferably, the surfactant is one or a combination of fatty alcohol polyoxyethylene ether sodium sulfate, sodium dodecyl sulfate, benzalkonium chloride, polysorbate.

[0015] Preferably, the modified nitrogen heterocyclic accelerator is composed of the following raw materials in percentage by mass:

[0016]

[0017] A second aspect of the present invention provides a method for preparing a semiconductor ceramic plate thin copper etching solution, comprising the following steps:

[0018] (1) preparing a modified nitrogen heterocyclic accelerator;

[0019] (2) First, add a portion of deionized water into the etching tank, then add sulfuric acid, sodium persulfate, modified nitrogen heterocyclic accelerator, and surfactant into the etching tank in sequence, and finally add the remaining deionized water.

[0020] Preferably, the preparation method of the modified nitrogen heterocyclic accelerator comprises the following steps:

[0021] Mix 2-aminoethanol and deionized water and put them into a reaction kettle, keep stirring, heat to 160-180°C, add thiazolinamide, react at constant temperature for 2-4h, then heat to 230-250°C, add 1-chlorobenzotriazole, react at constant temperature for 1-2h, then heat to 260-280°C and react for 0.5-1h to obtain a modified nitrogen heterocyclic accelerator.

[0022] Preferably, the modified nitrogen heterocyclic accelerator is prepared within 24 hours before preparing the semiconductor ceramic plate thin copper etching solution.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. Under the synergistic effect of the modified nitrogen heterocyclic accelerator and other raw materials in the ratio, the present invention does not corrode titanium metal, but only forms an etching effect on copper metal. The lateral corrosion of the ceramic substrate circuit after etching is small, and the etching factor is high. At the same time, the etching liquid has a stable etching rate, high tolerance to copper ions, low consumption, long liquid life, high processing capacity, and the copper surface after etching is free of oxidation and dirt, and has a reddish and bright color.

[0025] 2. The modified nitrogen heterocyclic accelerator of the present invention can interact with sodium persulfate to form an active intermediate, which can significantly increase the reaction rate of the etching solution and promote the decomposition of sodium persulfate, so that it can generate sulfate radicals (SO4. - ) and hydroxyl radicals ( · OH), and secondly, the modified nitrogen heterocyclic accelerator can enhance the selectivity of the reaction and does not react with titanium metal. The structure and properties of the nitrogen heterocyclic ring can guide the free radicals generated by sodium persulfate to react with copper metal first, improve the etching efficiency of copper metal, and reduce the occurrence of side reactions.

[0026] The presence of the modified nitrogen heterocyclic accelerator can enable sodium persulfate to play an effective oxidation role, so that the reaction system can perform well under different environmental conditions. Since the modified nitrogen heterocyclic accelerator improves the reaction efficiency of sodium persulfate, the amount of sodium persulfate can be reduced while achieving the same treatment effect, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic diagram of measuring the etching factor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] Embodiment 1 of the present invention provides a semiconductor ceramic plate thin copper etching solution, which is composed of the following raw materials in percentage by mass:

[0032] Sulfuric acid 8%; sodium persulfate 6%; modified nitrogen heterocyclic accelerator 2%; surfactant 1%; deionized water 83%.

[0033] The concentration of the sulfuric acid is 50wt% and the concentration of the sodium persulfate is 99%.

[0034] The surfactant is sodium fatty alcohol polyoxyethylene ether sulfate.

[0035] The modified nitrogen heterocyclic accelerator is composed of the following raw materials in percentage by mass:

[0036] 2-aminoethanol 67.3%; dithiothiophene 9.6%; 1-chlorobenzotriazole 3.8%; deionized water 19.3%.

[0037] According to the volume of 1L, the preparation method of the semiconductor ceramic plate thin copper etching solution comprises the following steps:

[0038] (1) preparing a modified nitrogen heterocyclic accelerator;

[0039] (2) First add 400 ml of deionized water to the etching tank, then add sulfuric acid to the etching tank, stir for 5 minutes, then add sodium persulfate, stir for 10 minutes, then add modified nitrogen heterocyclic accelerator, stir for 10 minutes, then add surfactant, stir for 10 minutes, and finally add deionized water to 1L in the etching tank and stir for 10 minutes.

[0040] The modified nitrogen heterocyclic accelerator is prepared within 24 hours before preparing the semiconductor ceramic plate thin copper etching solution. The preparation method of the modified nitrogen heterocyclic accelerator comprises the following steps:

[0041] 2-Aminoethanol and deionized water were mixed and put into a reactor, and stirred continuously. After the temperature was raised to 170°C, thiazolinamide was added, and the reaction was carried out at a constant temperature for 3 hours. Then, the temperature was raised to 240°C, 1-chlorobenzotriazole was added, and the reaction was carried out at a constant temperature for 1.5 hours. The temperature was then raised to 270°C and the reaction was carried out for 1 hour to obtain a modified nitrogen heterocyclic accelerator.

[0042] Example 2

[0043] Embodiment 1 of the present invention provides a semiconductor ceramic plate thin copper etching solution, which is composed of the following raw materials in percentage by mass:

[0044] Sulfuric acid 9%; sodium persulfate 7%; modified nitrogen heterocyclic accelerator 3%; surfactant 1%; deionized water 80%.

[0045] The concentration of the sulfuric acid is 50wt% and the concentration of the sodium persulfate is 99%.

[0046] The surfactant is sodium lauryl sulfate.

[0047] The modified nitrogen heterocyclic accelerator is composed of the following raw materials in percentage by mass:

[0048] 2-aminoethanol 60%; dithiothiophene 10%; 1-chlorobenzotriazole 5%; deionized water 25%.

[0049] According to the volume of 1L, the preparation method of the semiconductor ceramic plate thin copper etching solution comprises the following steps:

[0050] (1) preparing a modified nitrogen heterocyclic accelerator;

[0051] (2) First add 400 ml of deionized water to the etching tank, then add sulfuric acid to the etching tank, stir for 5 minutes, then add sodium persulfate, stir for 10 minutes, then add modified nitrogen heterocyclic accelerator, stir for 10 minutes, then add surfactant, stir for 10 minutes, and finally add deionized water to 1L in the etching tank and stir for 10 minutes.

[0052] The modified nitrogen heterocyclic accelerator is prepared within 24 hours before preparing the semiconductor ceramic plate thin copper etching solution. The preparation method of the modified nitrogen heterocyclic accelerator comprises the following steps:

[0053] 2-Aminoethanol and deionized water were mixed and put into a reactor, and the mixture was stirred continuously. After the temperature was raised to 160°C, thiazolinamide was added, and the mixture was reacted at a constant temperature for 4 hours. The temperature was then raised to 230°C, 1-chlorobenzotriazole was added, and the mixture was reacted at a constant temperature for 2 hours. The mixture was then raised to 260°C and reacted for 1 hour to obtain a modified nitrogen heterocyclic accelerator.

[0054] Example 3

[0055] Embodiment 1 of the present invention provides a semiconductor ceramic plate thin copper etching solution, which is composed of the following raw materials in percentage by mass:

[0056] Sulfuric acid 9.5%; sodium persulfate 7.5%; modified nitrogen heterocyclic accelerator 3.5%; surfactant 1.3%; deionized water 78.2%.

[0057] The concentration of the sulfuric acid is 50wt% and the concentration of the sodium persulfate is 99%.

[0058] The surfactant is benzalkonium chloride.

[0059] The modified nitrogen heterocyclic accelerator is prepared within 24 hours before preparing the semiconductor ceramic plate thin copper etching solution. The modified nitrogen heterocyclic accelerator is composed of the following raw materials in percentage by mass:

[0060] 2-aminoethanol 65%; dithiothiophene 10%; 1-chlorobenzotriazole 5%; deionized water 20%.

[0061] According to the volume of 1L, the preparation method of the semiconductor ceramic plate thin copper etching solution comprises the following steps:

[0062] (1) preparing a modified nitrogen heterocyclic accelerator;

[0063] (2) First add 400 ml of deionized water to the etching tank, then add sulfuric acid to the etching tank, stir for 5 minutes, then add sodium persulfate, stir for 10 minutes, then add modified nitrogen heterocyclic accelerator, stir for 10 minutes, then add surfactant, stir for 10 minutes, and finally add deionized water to 1L in the etching tank and stir for 10 minutes.

[0064] The preparation method of the modified nitrogen heterocyclic accelerator comprises the following steps:

[0065] 2-Aminoethanol and deionized water were mixed and put into a reactor, and the mixture was stirred continuously. After the temperature was raised to 170°C, thiazolinamide was added, and the mixture was reacted at a constant temperature for 3 hours. The temperature was then raised to 240°C, 1-chlorobenzotriazole was added, and the mixture was reacted at a constant temperature for 1.5 hours. The temperature was then raised to 270°C, and the mixture was reacted for 0.8 hours to obtain a modified nitrogen heterocyclic accelerator.

[0066] Example 4

[0067] Embodiment 1 of the present invention provides a semiconductor ceramic plate thin copper etching solution, which is composed of the following raw materials in percentage by mass:

[0068] Sulfuric acid 10%; sodium persulfate 8%; modified nitrogen heterocyclic accelerator 4%; surfactant 1.5%; deionized water 76.5%.

[0069] The concentration of the sulfuric acid is 50wt% and the concentration of the sodium persulfate is 99%.

[0070] The surfactant is polysorbate.

[0071] The modified nitrogen heterocyclic accelerator is prepared within 24 hours before preparing the semiconductor ceramic plate thin copper etching solution. The modified nitrogen heterocyclic accelerator is composed of the following raw materials in percentage by mass:

[0072] 2-aminoethanol 70%; dithiothreitol 10%; 1-chlorobenzotriazole 2%; deionized water 18%.

[0073] According to the volume of 1L, the preparation method of the semiconductor ceramic plate thin copper etching solution comprises the following steps:

[0074] (1) preparing a modified nitrogen heterocyclic accelerator;

[0075] (2) First add 400 ml of deionized water to the etching tank, then add sulfuric acid to the etching tank, stir for 5 minutes, then add sodium persulfate, stir for 10 minutes, then add modified nitrogen heterocyclic accelerator, stir for 10 minutes, then add surfactant, stir for 10 minutes, and finally add deionized water to 1L in the etching tank and stir for 10 minutes.

[0076] The preparation method of the modified nitrogen heterocyclic accelerator comprises the following steps:

[0077] Mix 2-aminoethanol and deionized water and put them into a reaction kettle, keep stirring, heat to 160-180°C, add thiazolinamide, react at constant temperature for 2-4h, then heat to 230-250°C, add 1-chlorobenzotriazole, react at constant temperature for 1-2h, then heat to 260-280°C and react for 0.5-1h to obtain a modified nitrogen heterocyclic accelerator.

[0078] Comparative Example:

[0079] A semiconductor ceramic substrate thin copper etching solution, which is composed of the following raw materials in percentage by mass:

[0080] Sulfuric acid 10%; Sodium persulfate 8%; Surfactant 1%; Deionized water 81%.

[0081] Wherein, the surfactant is sodium fatty alcohol polyoxyethylene ether sulfate.

[0082] Experimental example

[0083] Etching rate determination:

[0084] 1) Take a double-sided copper-clad laminate, place it in an oven at 120±5℃ for 10 minutes, and cool it to room temperature in a desiccator (copper thickness ≥10um);

[0085] 2) Weigh W1 using an electronic balance (unit: grams, please be accurate to 2 to 3 decimal places);

[0086] 3) The copper-clad laminate is passed through the etching tank at a set time or transmission speed, and the processing time T (min) is recorded;

[0087] 4) After washing with water, blow dry and place in an oven at 120±5℃ for 10 minutes, and cool to room temperature in a desiccator;

[0088] 5) Weigh W2 using an electronic balance (unit: grams, please be accurate to 2 to 3 decimal places);

[0089] 6) Measure the area S of the test board (the sum of the areas of both sides, unit: cm 2 )

[0090] 7) Calculation: Etching rate (um) = {(W1-W2) / (8.96×S)}×10000.

[0091] Under the same conditions, the etching solutions of Examples 1 to 4 of the present invention and the comparative example respectively etched ceramic substrates and copper-clad laminates of the same specifications.

[0092] Etching uniformity measurement:

[0093] 1. Take double-sided copper clad laminate (sheet size can be cut to 500mm×600mm);

[0094] 2. Use a copper thickness measuring instrument to measure the copper thickness at points on both sides of the board and keep records;

[0095] 3. Etch the copper plate according to the normal etching process, and measure the copper thickness at the same point and keep records.

[0096] Calculation method: [1-(maximum value - minimum value) / (average value × 2)] × 100%

[0097] Etching factor determination:

[0098] Cut the ceramic substrate treated with etching solution into slices of suitable size with circuits;

[0099] Use a grinder for grinding and polishing;

[0100] Measured under a metallographic microscope with a magnification of 200-500 times Figure 1 The parameters of a, b, and h are shown;

[0101] Calculation method: Etching factor = 2h / (ba)

[0102] Performance data comparison:

[0103]

[0104] As can be seen from the above table, the semiconductor ceramic substrate thin copper etching solution of the present invention has a significant improvement effect on the etching rate under the synergistic effect of the nitrogen heterocyclic accelerator and other components, and inhibits the corrosion of titanium metal, only etches copper metal, has a high etching factor, and the etching uniformity is improved. The tolerance of copper ions in the solution is also significantly improved.

[0105] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A semiconductor ceramic plate thin copper etching solution, characterized in that: The etching solution is composed of the following raw materials in percentage by mass: Wherein, the chemical structural formula of the modified nitrogen heterocyclic accelerator is as follows:

2. A semiconductor ceramic plate thin copper etching solution according to claim 1, characterized in that, The concentration of the sulfuric acid is 50 wt %.

3. A semiconductor ceramic plate thin copper etching solution according to claim 1, characterized in that, The concentration of the sodium persulfate is 99%.

4. A semiconductor ceramic plate thin copper etching solution according to claim 1, characterized in that, The surfactant is one of fatty alcohol polyoxyethylene ether sodium sulfate, sodium lauryl sulfate, benzalkonium chloride, polysorbate or a combination thereof.

5. A semiconductor ceramic plate thin copper etching solution according to claim 1, characterized in that, The modified nitrogen heterocyclic accelerator is composed of the following raw materials in percentage by mass:

6. A method for preparing a semiconductor ceramic plate thin copper etching solution according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) preparing a modified nitrogen heterocyclic accelerator; (2) First, add a portion of deionized water into the etching tank, then add sulfuric acid, sodium persulfate, modified nitrogen heterocyclic accelerator, and surfactant into the etching tank in sequence, and finally add the remaining deionized water.

7. The method for preparing a semiconductor ceramic plate thin copper etching solution according to claim 6, characterized in that: The preparation method of the modified nitrogen heterocyclic accelerator comprises the following steps: Mix 2-aminoethanol and deionized water and put them into a reaction kettle, keep stirring, heat to 160-180°C, add thiazolinamide, react at constant temperature for 2-4h, then heat to 230-250°C, add 1-chlorobenzotriazole, react at constant temperature for 1-2h, then heat to 260-280°C and react for 0.5-1h to obtain a modified nitrogen heterocyclic accelerator.

8. The method for preparing a semiconductor ceramic plate thin copper etching solution according to claim 6, characterized in that: The modified nitrogen heterocyclic accelerator is prepared within 24 hours before preparing the semiconductor ceramic plate thin copper etching solution.

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