Platinum chemical plating solution, preparation method thereof and application of platinum chemical plating solution in semiconductors

Abstract

The invention discloses a platinum chemical plating solution and a preparation method and application thereof in semiconductors, the platinum chemical plating solution comprises the following raw materials: 0.5-10.0 g / L of platinum salt PEP, 2.1-10.0 g / L of ethylenediamine sulfate, 1.2-8.9 g / L of malonic acid, 5-50 g / L of ammonium acetate, 1.2-9.2 g / L of thiourea dioxide, and the balance of ultrapure water and ammonia water; and the pH value of the solution is adjusted to 7.0 by ammonia water. The platinum chemical plating solution disclosed by the invention is suitable for nano precision manufacturing and processing on the surface of an electronic element product of a semiconductor device, and a formed platinum metal film has excellent uniform distribution, compactness and high wear resistance; a semiconductor electronic component product with excellent plugging performance, corrosion resistance, high-precision conductivity and high-quality electronic signal transmission performance is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of chemical platinum plating, in particular to a platinum chemical plating solution and a preparation method thereof and application in semiconductors. Background Art

[0002] Semiconductor electronic components are important raw materials for integrated circuits. Chemical plating deposition of semiconductor devices is a special manufacturing technology in the nano-precision manufacturing process of semiconductor electronic components. It is the only key technology that can achieve nano-level electronic logic interconnection and micro-nano structure manufacturing and processing. Application areas include semiconductor wafer chip plating, semiconductor lead frame plating, printed circuit board plating, connector plating, microwave devices and other electronic component manufacturing. It involves chemical plating deposition on the surface of semiconductor electronic components to form nano-level metal films and microstructures.

[0003] In the micromachining process of the surface of semiconductor electronic components, metal ions in the chemical plating solution are reduced, for example, platinum ions undergo a reduction chemical reaction on the surface of semiconductor devices to form a platinum metal film. This method requires precise control of the uniform distribution, morphology, density and high wear resistance of the platinum metal film in order to obtain excellent pluggability, high corrosion resistance, high-precision conductivity and high-quality electronic signal transmission performance.

[0004] The miniaturization and multifunctionality of semiconductor electronic products continue to promote the development of integrated circuits in the direction of fine circuits and miniaturization of volume. Its mainstream products are HDI (high-density interconnect) boards and IC (integrated circuit) substrates. In order to meet the high-density and high-integration requirements of HDI and IC substrates, the nano-precision manufacturing technology of electronic electroplating has been pioneered in the semiconductor device manufacturing industry chain.

[0005] With the increasing demand for nano-precision manufacturing technology of chemical platinum plating, the improvement of plating process and the continuous updating of chemical plating solution in the nano-precision manufacturing technology of chemical platinum plating are particularly important. High-end semiconductor device products have very strict evaluation requirements on the excellent density, high uniformity, excellent plug-in performance and strong corrosion resistance of platinum metal coating in various harsh environments. Only by meeting these requirements can the semiconductor electronic products produced have high-precision conductivity and high-quality electronic signal transmission performance. The above requirements are important technical indicators for measuring the manufacturing process of chemical deposition nano-metal plating in semiconductor electronic component products.

[0006] Common reducing agents used in chemical platinum plating solutions in the prior art include boron hydride compounds, aminoborane compounds, formaldehyde, hydrazine compounds or o-diphenol compounds. Among them, some reducing agents have strong reducing properties, making it difficult to control the reaction process, resulting in uneven coating; secondly, some reducing agents have poor stability and require the addition of stabilizers to be effectively used. However, increasing the components of the electroplating solution system makes the electroplating solution system more complicated, which will shorten the service life of the electroplating solution.

[0007] In the prior art, CN110621806A uses borohydride as a reducing agent, JP2016-160505A uses sodium borohydride as a reducing agent, JP2018-104755A uses borohydride, aminoborane compounds or hydrazine compounds as a reducing agent, JP2017-75379A uses formalin, glucose and formate as reducing agents, and CN109415812A uses formic acid as a reducing agent. These technical solutions cannot precisely control the uniform distribution, morphology, wear resistance and density of the platinum metal film, and cannot meet the deposition and formation of nanostructured electronic transmission lines on the surface of semiconductor electronic components.

[0008] In summary, in the field of platinum chemical plating technology for semiconductor electronic component products, there is an urgent need to find a chemical plating solution and equipment process solution to solve problems such as tiny pinholes and cracks in the platinum coating, especially focusing on solving the technical difficulty of the lack of friction resistance of the platinum coating. Summary of the invention

[0009] In view of the above problems existing in the prior art, the present invention provides a platinum chemical plating solution and a preparation method thereof and application in semiconductors. The platinum chemical plating solution of the present invention can be applied to nano-precision manufacturing and processing of the surface of semiconductor device electronic component products, and the formed platinum metal film has excellent uniform distribution, compactness and high wear resistance, and obtains semiconductor electronic component products with excellent pluggability, corrosion resistance, high-precision conductivity and high-quality electronic signal transmission performance.

[0010] The technical solution of the present invention is as follows: The first object of the present invention is to provide a platinum chemical plating solution, comprising the following raw materials: 0.5-10.0 g / L of platinum salt PEP, 2.1-10.0 g / L of ethylenediamine sulfate, 1.2-8.9 g / L of malonic acid, 5-50 g / L of ammonium acetate, 1.2-9.2 g / L of thiourea dioxide, and the balance being ultrapure water and ammonia water; the ammonia water is used to adjust the pH value of the solution to 7.0.

[0011] In one embodiment of the present invention, the structure of the platinum salt PEP is shown in formula (1): Formula (1).

[0012] The CAS number of platinum salt PEP is: 41666-77-7.

[0013] In one embodiment of the present invention, the concentration of ethylenediamine sulfate is 6.1 g / L.

[0014] In one embodiment of the present invention, the concentration of thiourea dioxide is 5.2 g / L.

[0015] In one embodiment of the present invention, the concentration of malonic acid is 4.9 g / L.

[0016] A second object of the present invention is to provide a method for preparing the above-mentioned platinum chemical plating solution, comprising the following steps: (1) Preparation of the starter solution A: Based on the final concentration of each component in the platinum chemical plating solution, ethylenediamine sulfate, ammonium acetate and platinum salt PEP (II) are completely dissolved in an appropriate amount of ultrapure water under heating and stirring conditions, and the pH value of the solution is adjusted to 7 with ammonia water to obtain the starter solution A; (2) Preparation of starter solution B: Based on the final concentration of each component in the platinum chemical plating solution, completely dissolve thiourea dioxide in an appropriate amount of ultrapure water under heating and stirring conditions, adjust the pH value of the solution to 7, and then add malonic acid to adjust the pH value of the solution to 7 to obtain starter solution B; (3) Compounding: Add the pre-bottle liquid B to the pre-bottle liquid A, mix well, and test the solution pH to 7. Use ultrapure water to make up the volume. During chemical plating, adjust the solution pH to 10.0 to obtain a platinum chemical plating solution.

[0017] In one embodiment of the present invention, the heating and stirring conditions are: 100 rpm at 50°C.

[0018] The third object of the present invention is to provide a method for preparing a coating using the above-mentioned platinum chemical plating solution, comprising the following steps: S1. Degreasing and acid activation treatment of the semiconductor electronic components to be processed; S2. Select the corresponding plating conditions according to the plating area and form of the plated part, and the solution temperature is 50~60 ℃; S3. During the plating process, an automatic analyzer is used to detect the concentration of platinum salt, thiourea dioxide concentration, and pH in the platinum chemical plating solution. Based on the difference between the test result and the solution control standard value, a linked automatic replenishing device is used to quantitatively add platinum salt PEP solution, thiourea dioxide, or pH adjuster; S4. After reaching the target coating thickness, stop plating to form a coating on the semiconductor electronic component.

[0019] In one embodiment of the present invention, during the plating process, the initial pH value of the platinum chemical plating solution is 7.0. After the semiconductor device is placed in the plating solution, the pH is detected in real time to control the pH value range to 9.5-10.5, so that thiourea dioxide is promoted to reduce Pt (II) to Pt (0) under the pH conditions; the pH value is controlled based on the results of real-time testing, with pH 10.0 as the standard, and 0.1 mol / L sodium hydroxide solution is automatically added to maintain the pH of the plating solution at the standard value of 10.

[0020] After completing the plating work of batches of semiconductor electronic components, when it is necessary to stop continuous production for a period of time, the solution pH automatic analysis and linkage automatic replenishment equipment system will adjust the pH 10 solution in the production state to pH 7 with sulfuric acid solution and then store it.

[0021] The fourth object of the present invention is to provide a semiconductor device electronic product with excellent plug-in and pull-out performance, having a dense platinum coating, uniform film thickness distribution and high friction resistance; in particular, an experimental procedure and a detection method for detecting the porosity of a chemically plated platinum layer through a nitric acid vapor test, as well as a platinum coating wear test and a plug-in and pull-out test of the product are provided to test the conductive stability of the electronic product, which is used to evaluate and distinguish the friction resistance and plug-in and pull-out performance of semiconductor electronic component nanostructured electronic products, and to provide semiconductor component products with both high-precision conductivity and high-quality electronic signal transmission performance.

[0022] The present invention conducts a nitric acid vapor experiment on the platinum coating and studies the ratio of the corroded area to the total coating area. It is found that the smaller the proportion of the corroded area of ​​the platinum coating, the stronger the corrosion resistance of the platinum-plated product. Conversely, the larger the corroded area, the worse the corrosion resistance.

[0023] Furthermore, after the nitric acid vapor experiment on the platinum-plated semiconductor electronic circuit board, the circuit impedance is tested. The smaller the impedance change before and after the experiment, the better the corrosion resistance of the platinum coating.

[0024] Furthermore, from the platinum coating wear test, it can be seen from the platinum coating mass wear before and after the wear test that the smaller the difference is, the stronger its wear resistance is.

[0025] Furthermore, after the platinum-plated semiconductor electronic circuit board is subjected to a plug-in experiment, its circuit impedance is tested. The smaller the impedance change before and after the experiment, the better the plug-in resistance of the platinum coating is.

[0026] The beneficial technical effects of the present invention are: The present invention adopts platinum salt PEP with five-membered and six-membered bicyclic structures, ethylenediamine sulfate as a complexing agent, thiourea dioxide as a reducing agent, and malonic acid as an additive; the present invention realizes nano-precision manufacturing and processing of semiconductor electronic products by optimizing the platinum salt PEP, the complexing agent, the reducing agent and the additive and controlling them within a suitable concentration range, and the formed platinum metal film has excellent morphology, uniform distribution, high wear resistance and excellent compactness, and the produced semiconductor electronic products have excellent pluggability, corrosion resistance, high-precision conductivity and high-quality electronic signal transmission performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a coordinate diagram of the film thickness test of semiconductor coatings; Figure 2 An enlarged schematic diagram of a semiconductor device unit; In the figure, 10, semiconductor plated part, 11, semiconductor device unit, 12, film thickness test point. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0029] Substrate: The structure of the semiconductor device plated part 10 to be processed by chemical plating is as follows Figure 1 As shown, chemical platinum plating is performed on a single side of each unit 11 at the same time.

[0030] The semiconductor plated test piece to be processed in this embodiment is as follows Figure 1 As shown in 10, the copper alloy material is 250×79.2 mm and the thickness is 0.127 mm; there are 96 electronic plating units in total. The plating area 11 of each unit is 0.5×10×7=35mm 2 Therefore, the total area of ​​a single side of a semiconductor plated piece is 96×35 mm 2 =3360 mm 2 .

[0031] After the semiconductor plated part 10 is subjected to alkali degreasing and acid activation treatment, a bottom nickel plating treatment is performed, and the nickel film thickness is 1300~700 nm; then, it is immersed in a plating equipment, and the platinum chemical plating solution prepared in the embodiment is added to the mother tank of the plating equipment. The tank temperature is 55°C, and the semiconductor plated part is chemically plated for 58 minutes. The target thickness of the platinum coating of the semiconductor plated part 10 is set to 300 nm; the plating conditions of Example 1 are listed in Table 1.

[0032] Table 1

[0033] Test method: Platinum coating thickness test: Fischer FISCHERSCOPE X-RAY XDV-SDD tester Figure 1 The electroplating area of ​​each unit 11 is as follows Figure 2The central black dot 12 shown has coordinates of: 16 (10.0 mm, 6.5 mm), 15 (10.0, 24.0), 14 (10.0, 37.5), 13 (10.0, 55.5), 12 (10.0, 69.0), 11 (10.0, 87.0), 10 (10.0, 100.5), 9 (10.0, 118.0), 8 (10.0, 131.5), 7 (10.0, 149.0) 6 (10.0, 161.0), 5 (10.0, 178.5), 4 (10.0, 190.5), 3 (10.0, 208.0), 2 (10.0, 220.0), 1 (10.0, 237.5.0) in column I; 16 (22.0mm, 6.5mm), 15 (22.0, 24.0), 14 (22.0, 37.5), 13 (22.0, 55.5), 12 (22.0, 69.0), 11 (22.0, 87.0), 10 (22.0, 100.5), 9 (22.0, 118.0), 8 (22.0, 131.5), 7 (22.0, 149.0) 6 (22.0, 161.0), 5 (22.0, 178.5), 4 (22.0, 190.5), 3 (22.0, 208.0), 2 (22.0, 220.0), 1 (22.0, 237.5.0); 16 (34.0mm, 6.5mm) for row III , 15 (34.0, 24.0), 14 (34.0, 37.5), 13 (34.0, 55.5), 12 (34.0, 69.0), 11 (34.0, 87.0), 10 (34.0, 100.5), 9 (34.0, 118.0), 8 (34.0, 131.5), 7 (34.0, 149.0) 6 (34.0, 161.0), 5 (34.0, 178.5), 4 (34.0, 190.5), 3 (34.0, 208.0), 2 (34.0, 220.0), 1 (34.0, 237.5.0); 16 (46.0mm, 6.5mm), 15 (46.0, 24.0), 14 (46.0, 37.5), 13 (46.0, 55.5), 12 (46.0, 69.0), 11 (46.0, 87.0), 10 (46.0, 100.5), 9 (46.0, 118.0), 8 (46.0, 131.5), 7 (46.0, 149.0) 6 (46.0, 161.0), 5 (46.0, 178.5), 4 (46.0, 190.5), 3 (46.0, 208.0), 2 (46.0, 220.0), 1 (46.0, 237.5.0); Ⅴ column 16 (58.0mm, 6.5mm), 15 (58.0, 24.0), 14 (58.0, 37.5), 13 (58.0, 55.5), 12 (58.0, 69.0), 11 (58.0, 87.0), 10 (58.0, 100.5), 9 (58.0, 118.0), 8 (58.0, 131.5), 7 (58.0, 149.0) 6 (58.0, 161.0), 5 (58.0, 178.5), 4 (58.0, 190.5), 3 (58.0, 208.0), 2 (58.0, 220.0), 1 (58.0, 237.5.0); 16 (70.0 mm, 6.5 mm), 15 (70.0 , 24.0), 14 (70.0, 37.5), 13 (70.0, 55.5), 12 (70.0, 69.0), 11 (70.0, 87.0), 10 (70.0, 100.5), 9 (70.0, 118.0), 8 (70.0, 131.5), 7 (70.0, 149.0) 6 (70.0, 161.0), 5 (70.0, 178.5), 4 (70.0, 190.5), 3 (70.0, 208.0), 2 (70.0, 220.0), 1 (70.0, 237.5.0). .

[0034] Analyze the platinum coating film thickness data Max, Min, Ave., Max-Min and film thickness error value.

[0035] The platinum film thickness error calculation formula is as follows.

[0036]

[0037] Appearance inspection of chemically platinum-plated semiconductor device products: Appearance inspection, observation with an electron microscope at 300 times magnification, the results are judged according to the following standards; Excellent: The platinum coating should be uniform, smooth, free of bubbles, pits, scratches, missing plating, penetration and other defects, and is evaluated as excellent.

[0038] Good: The platinum coating is uniform, smooth, free of bubbles, pits, scratches, missing plating, and infiltration, and the defect area is less than 3% of the overall test area, which is evaluated as good.

[0039] Medium: The platinum coating is uniform, smooth, free of bubbles, pits, scratches, missing plating, and penetration plating. The defect area is greater than 3% of the overall test area, and the defect area is less than 5% of the overall test area. It is evaluated as medium.

[0040] Bad: The platinum coating is not uniform, smooth, has no bubbles, no pits, no scratches, no missing plating, no seepage plating, etc. The defect area is greater than 5% of the overall test area and is evaluated as unqualified.

[0041] Nitric acid vapor test and detection of chemically platinum-plated semiconductor device products: The test was carried out according to the national standard GB / T 19351-2003 implementation method; each example sample was cut into four chips as a group, and the experimental time was 2 hours. After the test, the corrosion area caused by tiny pinholes and slits was detected using a 3D profile measuring instrument VR-6000 manufactured by Keyence. The percentage of the corrosion area to the total area of ​​the plating area is called the corrosion rate; the lower the corrosion rate, the fewer tiny pinholes and slits, and the higher the corrosion resistance of the plated platinum metal; conversely, the higher the corrosion rate, the more tiny pinholes and slits, and the lower the corrosion resistance of the plated platinum metal.

[0042] Surface roughness test of platinum coating of chemically platinum-plated semiconductor device products: The test is carried out according to the national standard GB / T3505-2000, and the surface roughness is tested using the 3D profile measuring instrument VR-6000 manufactured by Keyence. The result is expressed as the arithmetic mean value Ra in nm.

[0043] Platinum coating wear test of chemically platinum-plated semiconductor device products: implemented in accordance with national standard GB-T 12444-2006, using CSM ball friction and wear test equipment.

[0044] The contact resistance test of the platinum-plated electrical contacts of chemically platinum-plated semiconductor device circuit boards is carried out in accordance with the national standard "Measurement method of contact resistance of precious metal electrical contacts" GB / T 15078-2021. Test samples: 1. Samples of platinum-plated semiconductor device circuit boards before and after the nitric acid vapor test; 2. Samples of platinum-plated semiconductor device circuit boards before and after the plug-in test.

[0045] Plugging and unplugging test conditions: 1000 times; plugging and unplugging counts as one time.

[0046] Criteria: 1. Average resistance difference before and after the experiment △Ω: 0 mΩ ≤ △Ω ≤0.5 mΩ Excellent 2. 0.5 mΩ<△Ω≤1.0 mΩ Good 3. 1.0 mΩ<△Ω≤5.0 mΩ qualified 4. 5.0 mΩ<△Ω≤∞ mΩ Unqualified Example 1 A platinum chemical plating solution includes components with concentrations as described in Table 2 below: Table 2

[0047] The preparation method of the above-mentioned platinum chemical plating solution comprises the following steps: (1) Preparation of starter solution A: Based on the final concentration of each component in the platinum chemical plating solution, ethylenediamine sulfate 2.1 g / L, ammonium acetate 20 g / L, platinum salt PEP (II) 1.5 g / L (calculated as platinum), completely dissolve ethylenediamine sulfate, ammonium acetate and platinum salt PEP (II) in an appropriate amount of ultrapure water under heating (50 °C) and stirring conditions, and adjust the solution pH to 7 with ammonia water to obtain starter solution A; (2) Preparation of starter solution B: Based on the final concentration of each component in the platinum chemical plating solution, 2.5 g / L of thiourea dioxide and 2.4 g / L of malonic acid were used. Under heating (50 °C), thiourea dioxide was completely dissolved in an appropriate amount of ultrapure water. The pH value of the solution was adjusted to 7, and then malonic acid was added to adjust the pH value of the solution to 7 to obtain starter solution B. (3) Compounding: Slowly add the pre-bottle liquid B to the pre-bottle liquid A, mix well, and test the solution pH to 7. Use ultrapure water to make up the volume. During chemical plating, adjust the solution pH to 10.0 to obtain a platinum chemical plating solution.

[0048] During chemical plating, a pH adjuster (such as ammonia water and / or sodium hydroxide solution) is used to adjust the pH value of the platinum chemical plating solution to 10.0; when chemical plating is not required, a pH adjuster (such as at least one of ammonia water, sodium hydroxide solution or sulfuric acid solution) is used to adjust the pH value of the platinum chemical plating solution to 7.

[0049] The use of the above-mentioned platinum chemical plating solution in the preparation of a platinum-plated semiconductor electronic component product, wherein a platinum nanostructured coating is formed on the surface of the platinum-plated semiconductor electronic component product, comprises the following steps: The semiconductor electronic plated part 10 to be chemically plated is installed in the chemical plating equipment, and the above-mentioned platinum chemical plating solution is used for chemical plating for 47 minutes at a platinum chemical plating solution temperature of 55°C and a pH value of 9.5-10.5 (for example, 10.0), so as to obtain a semiconductor electronic component product with a plating layer having a platinum film thickness of ≥300 nm.

[0050] The platinum coating thickness (nm) results of Example 1 are shown in Table 3.

[0051] Table 3

[0052] As can be seen from Table 3, the platinum chemical plating solution of Example 1 is used to prepare platinum-plated semiconductor electronic products, and the platinum coating film thickness is 302-308 nm; the maximum film thickness and the minimum film thickness difference Max-Min is 6 nm; the error of its maximum value compared with the target setting value of 300 nm is (308-300) / 300=2.7%; it shows that the film thickness error of the platinum chemical plating solution of Example 1 is ≤2.7%, and has good uniformity of film thickness distribution.

[0053] Example 2 to Example 9 Complexing agent concentration optimization A platinum chemical plating solution and a preparation method thereof are described with reference to Example 1, except that the concentration of the complexing agent ethylenediamine sulfate is adjusted according to Table 4.

[0054] Table 4

[0055] The application of the above-mentioned platinum chemical plating solution in the preparation of platinum-plated semiconductor electronic component products is described in Example 1.

[0056] Test Example 1: The platinum-plated semiconductor electronic component products obtained in Examples 1 to 9 were tested for the thickness of the platinum coating (unit: nm). The results are shown in Table 5.

[0057] Table 5

[0058] As can be seen from Table 5, the platinum chemical plating solutions of Examples 1 to 9 are used to prepare platinum-plated semiconductor device products, and the platinum coating film thickness ranges from 301 to 307 nm; the Max-Min maximum film thickness and the minimum film thickness difference is 3 to 6 nm; the error of its maximum value compared to the target setting value of 300 nm is 2.0 to 2.3%, indicating that the platinum chemical plating solutions of Examples 1 to 9 have good uniformity in film thickness distribution.

[0059] The platinum-plated semiconductor electronic component products obtained in Examples 1 to 9 were subjected to appearance inspection, corrosion resistance test, platinum coating surface roughness test and platinum coating purity test. The results are shown in Table 6.

[0060] Table 6

[0061] As shown in Table 6, the platinum chemical plating solutions of Examples 1 to 9 are applied to chemical platinum plating of semiconductor devices. In the platinum-plated semiconductor electronic component products obtained, the platinum metal film has excellent appearance detection by electron microscope 300 times, 0.0% corrosion rate in nitric acid vapor test for 2 hours, and the roughness of the platinum coating is 182 to 186 nm; further, its wear weight is only 0.7 to 0.9 mg; the above results confirm that the platinum-plated semiconductor electronic component products obtained in Examples 1 to 9, the formed platinum metal film has excellent morphology, uniform distribution, excellent density and high wear resistance, and the produced semiconductor device electronic products have excellent corrosion resistance and excellent plug-in performance, thus better ensuring the high-precision conductivity and high-quality electronic signal transmission performance of the platinum-plated semiconductor electronic component products. It can be seen that the concentration of the complexing agent ethylenediamine sulfate in the present invention has a significant effect on the comprehensive performance of the platinum coating. When the platinum salt PEP (in terms of Pt) is 1.5 g / L, the concentration of the complexing agent ethylenediamine sulfate can be selected in the range of 2.1 to 10 g / L; among which 6.1 g / L in Example 5 can be used as the most preferred embodiment.

[0062] Example 10-18 Optimization of reducing agent concentration A platinum chemical plating solution and a preparation method thereof are described with reference to Example 1, except that the concentration of the complexing agent diethylammonium sulfate is 6.1 g / L, and the concentration of the reducing agent thiourea dioxide is adjusted according to Table 7.

[0063] Table 7

[0064] The application of the above-mentioned platinum chemical plating solution in the preparation of platinum-plated semiconductor electronic component products is described in Example 1.

[0065] Test Example 2: The platinum-plated semiconductor electronic component products obtained in Examples 10 to 18 were tested for the thickness of the platinum coating (unit: nm). The results are shown in Table 8.

[0066] Table 8

[0067] As can be seen from Table 8, the platinum chemical plating solutions of Examples 10 to 18 are used to prepare platinum-plated semiconductor electronic component products, and the platinum coating film thickness ranges from 301 to 308 nm; the Max-Min maximum film thickness and the minimum film thickness difference is 3 to 6 nm; the maximum value has an error of 2.0 to 2.3% compared to the target setting value of 300 nm; it shows that the platinum chemical plating solutions of Examples 10 to 18 achieve good uniformity in film thickness distribution.

[0068] The platinum-plated semiconductor electronic component products obtained in Examples 10 to 18 were subjected to appearance inspection, corrosion resistance test, platinum coating surface roughness test and platinum coating purity test. The results are shown in Table 9.

[0069] Table 9

[0070] From the appearance test results of Examples 10 to 18 in Table 9, the nitric acid vapor corrosion rate test results, and the surface roughness test results of the platinum coating, the electron microscope 300 times appearance test of the platinum metal film is excellent, the nitric acid vapor test 2 hours corrosion rate is 0.0%, the platinum coating roughness is 182~186 nm, and further, the friction and wear test results of the platinum coating are only 0.6~0.9 mg; the above results confirm that the chemical platinum-plated semiconductor electronic component products prepared in Examples 10 to 18, the formed platinum metal film has excellent morphology, uniform distribution, excellent density and high friction resistance, and the produced semiconductor electronic component products have excellent corrosion resistance and excellent plug-in performance, thus better ensuring the high-precision conductivity and high-quality electronic signal transmission performance of the platinum-plated semiconductor electronic component products. It can be seen that the concentration of the reducing agent thiourea dioxide in the present invention has a significant effect on the comprehensive performance of the platinum coating, and the concentration of the reducing agent thiourea dioxide can be selected in the range of 1.2~9.2 g / L; wherein 5.2 g / L of Example 14 can be used as the most preferred embodiment.

[0071] Examples 19-27 Additive Concentration Optimization A platinum chemical plating solution and a preparation method thereof, referring to Example 1, the only difference is that the concentration of the complexing agent diethylammonium sulfate is 6.1 g / L, and the concentration of the reducing agent thiourea dioxide is 5.2 g / L; in addition, an additive malonic acid is added to the platinum chemical plating solution, and the concentration of the malonic acid is set according to Table 10.

[0072] Table 10

[0073] The application of the above-mentioned platinum chemical plating solution in the preparation of platinum-plated semiconductor electronic component products is described in Example 1.

[0074] Test Example 3: The thickness of the platinum coating (unit: nm) was tested for the chemically platinum-plated semiconductor electronic component products obtained in Examples 19 to 27. The results are shown in Table 11.

[0075] Table 11

[0076] As shown in Table 11, the thickness of the platinum coating ranges from 301 to 307 nm; the difference between the Max-Min maximum and minimum film thicknesses is 4 to 6 nm; the error of its maximum value compared to the target setting value of 300 nm is 2.0 to 2.3%, indicating that the platinum chemical plating solutions of Examples 19 to 27 achieve good uniformity in film thickness distribution.

[0077] The chemically platinum-plated semiconductor electronic component products obtained in Examples 19 to 27 were subjected to appearance inspection, corrosion resistance test, platinum coating surface roughness test and platinum coating purity test. The results are shown in Table 12.

[0078] Table 12

[0079] As can be seen from Table 12, according to the test results of the platinum chemical plating solution of Examples 19 to 27 for preparing platinum-plated semiconductor electronic component products, the appearance inspection of the platinum metal film under an electron microscope of 300 times is excellent, the corrosion rate of the nitric acid vapor test for 2 hours is 0.0%, and the roughness of the platinum coating is 182 to 186 nm. Further, the friction and wear test results of the platinum coating are only 0.6 to 0.8 mg; the above results confirm that the platinum metal film formed by the chemical plating semiconductor electronic component products prepared in Examples 19 to 27 has excellent morphology, uniform distribution, excellent density and high friction resistance, and the semiconductor device electronic component products produced have excellent corrosion resistance and excellent plug-in performance, thus better ensuring the high-precision conductivity and high-quality electronic signal transmission performance of the platinum-plated semiconductor electronic component products. It can be seen that the concentration of the additive malonic acid in the present invention has a significant effect on the comprehensive performance of the platinum coating, and the concentration of the additive malonic acid can be selected in the range of 1.2 to 8.9 g / L; wherein 4.9 g / L in Example 23 can be used as the most preferred embodiment.

[0080] In summary, in the platinum chemical plating solution provided by the present invention, the concentration range of the complexing agent ethylenediamine sulfate is 2.1~10.0 g / L, the concentration range of the reducing agent thiourea dioxide is 1.2~9.2 g / L, the concentration range of the additive malonic acid is 1.2~8.9 g / L, and the platinum salt PEP (in terms of Pt) is 1.5 g / L, which can exert the effective performance of the platinum chemical plating solution of the present invention.

[0081] From the above analysis, it can be seen that from the perspective of being used to prepare platinum-plated semiconductors and electronic components having excellent platinum coating appearance and excellent comprehensive performance, the best formula of the platinum chemical plating solution of the present invention is shown in Example 23, namely: The platinum chemical plating solution includes: 6.1 g / L ethylenediamine sulfate, 20 g / L ammonium acetate, 1.5 g / L platinum salt PEP complex (calculated as platinum), 4.9 g / L malonic acid, 5.2 g / L thiourea dioxide, and the solvent is ultrapure water; during chemical plating, a pH adjuster (such as ammonia water and / or sodium hydroxide solution) is used to adjust the pH value of the platinum chemical plating solution to 10.0; when chemical plating is not required, a pH adjuster (such as at least one of sodium hydroxide solution, ammonia water or sulfuric acid solution) is used to adjust the pH value of the platinum chemical plating solution to 7.

[0082] Furthermore, the test results of the circuit board resistance and difference (unit: mΩ) of the platinum-plated semiconductor electronic circuit board of Example 23 before and after the nitric acid vapor experiment are shown in Tables 13 and 14.

[0083] Table 13

[0084] Table 14

[0085] The difference results of the circuit board resistance (unit: mΩ) test of the platinum-plated semiconductor electronic circuit board of Example 23 before and after 1000 plug-in and pull-out experiments are shown in Table 15.

[0086] Table 15

[0087] It can be seen from Tables 13, 14 and 15 that the resistance difference results of the platinum-plated circuit board of Example 23 before and after the nitric acid vapor test and the plug-in test are 0.21-0.27 mΩ and 0.12-0.26 mΩ, respectively, which confirms that the platinum chemical plating solution of the present invention and the semiconductor electronic circuit board prepared therefrom still have excellent high-precision conductivity and high-quality electronic signal transmission performance even after the harsh nitric acid vapor test and the plug-in test.

[0088] Comparative Examples 1 to 12 Comparative Examples 1 to 4 are compared with Example 23, except that the concentration of the complexing agent ethylenediamine sulfate is different, and the other components are the same Comparative Examples 5 to 8 are compared with Example 23, except that the concentration of thiourea used as the reducing agent is different, and the other components are the same. Comparative Examples 9 to 12 are compared with Example 23, except that the concentration of the additive malonic acid is different, and the other components are the same The detailed preparation concentrations of Comparative Examples 1 to 12 are shown in Table 16.

[0089] Table 16

[0090] According to the same method as Example 1, a platinum chemical plating solution was prepared, and a platinum-plated product of a semiconductor electronic component was prepared. The appearance inspection, nitric acid vapor test, friction and wear test of the platinum coating and roughness test results are shown in Table 17.

[0091] Table 17

[0092] It can be seen from Table 17 that when the amount of the complexing agent of Comparative Examples 1 to 4, the reducing agent of Comparative Examples 5 to 8, and the additive of Comparative Examples 9 to 12 is lower or higher than the applicable scope of the present invention, the appearance inspection results of the coating can only reach poor, neutral, and good, which is very different from the excellent results of the preferred range of the present invention; the corrosion rate of the nitric acid vapor test for 2 hours is 0.6-2.5%, which is very different from the preferred result of 0.0% of Examples 19 to 27 of the present invention; the friction and wear weight is 1.5-3.2 mg, which is much higher than the friction and wear weight of 0.6-0.8 mg of Examples 19 to 27 of the present invention; the surface roughness is 255-263 nm, which is also much higher than the surface roughness of 182-186 nm of Examples 19 to 27 of the present invention; therefore, it can be seen that the low or high amount of the complexing agent, reducing agent and additive directly leads to the reduction of the performance of the platinum coating.

[0093] The above results further confirm that, in the platinum chemical plating solutions of Examples 19 to 27 provided by the present invention, the concentration range of the complexing agent ethylenediamine sulfate is 2.1 to 10.0 g / L, the concentration range of the reducing agent thiourea dioxide is 1.2 to 9.2 g / L, the concentration range of the additive malonic acid is 1.2 to 8.9 g / L, and the platinum salt PEP (in terms of Pt) is 1.5 g / L; these four components are the important basis for ensuring the various properties of the chemically deposited platinum coating of the semiconductor electronic products prepared by the present invention.

[0094] When the concentration of the platinum salt PEP (in terms of Pt) is changed in the platinum chemical plating solution of the present invention, the concentrations of the complexing agent ethylenediamine sulfate, the reducing agent thiourea dioxide and the additive malonic acid need to be adjusted simultaneously to exert the effective performance of the platinum chemical plating solution of the present invention.

[0095] Comparative Examples 13-20 The platinum chemical plating solutions and preparation methods thereof provided in Comparative Examples 13 and 14 refer to Example 23, and the concentrations of the complexing agent, conductive salt, platinum salt, reducing agent, additives, etc. remain unchanged. The only difference is that: Comparative Example 13 uses diammine dichloroplatinum instead of platinum salt PEP; Comparative Example 14 uses sodium borohydride instead of thiourea dioxide.

[0096] Comparative Example 15: A chemical plating solution was prepared according to Example 1 of CN109415812A, using potassium formate as a reducing agent; and the platinum salt was potassium platinum tetrachloride.

[0097] Comparative Example 16: A chemical plating solution was prepared according to Example a4 of CN110621806A using sodium borohydride and tetraammine platinum nitrate; Comparative Example 17: A chemical plating solution was prepared according to Example 1 of JP2018-104755A using sodium borohydride and dinitrodiammine platinum; Comparative Example 18: A chemical plating solution was prepared according to Example 1 of JP2017-75379A using sodium formate and tetraammineplatinum dichloride; Comparative Example 19: A chemical plating solution was prepared according to Example 1 of JP2016-160505A using sodium borohydride and ammonium chloroplatinate; Comparative Example 20: A chemical plating solution was prepared according to Example 28 of CN118668195A using thiourea dioxide and diamino compounds; The application of the above-mentioned platinum chemical plating solution in the preparation of platinum-plated semiconductor electronic component products is as shown in Example 1, and the pH adjustment and plating time are adjusted as shown in Table 18.

[0098] Table 18

[0099] Test Example 4: The platinum-plated semiconductor device products obtained in Comparative Examples 13 to 20 were tested for platinum coating film thickness (unit: nm). The results are shown in Table 19.

[0100] Table 19

[0101] The platinum-plated semiconductor electronic component products obtained in Comparative Examples 13 to 20 were subjected to appearance inspection, corrosion resistance test, platinum coating surface roughness test and platinum coating purity test, and the results are shown in Table 20.

[0102] Table 20

[0103] Note: The four combinations of ethylenediamine sulfate, thiourea dioxide, malonic acid and platinum salt PEP (measured in Pt) meet the concentration requirements.

[0104] Combining Tables 12, 17, and 20, it can be seen that the test results of the platinum chemical plating solutions of Examples 19 to 27 with the "four combinations" are applied to the preparation of platinum-plated semiconductor electronic component products. The platinum metal film has excellent appearance inspection under an electron microscope at 300 times, a 2-hour corrosion rate in a nitric acid vapor experiment of 0.0%, a platinum coating roughness of 182 to 186 nm, and a friction and wear test result of the platinum coating of only 0.6 to 0.8 mg. The above results fully confirm that the platinum metal film formed by the chemically platinum-plated semiconductor electronic component products obtained in Examples 19 to 27 has excellent morphology, uniform distribution, excellent density, and high friction resistance. The produced semiconductor electronic component products have excellent corrosion resistance and excellent plug-in and pull-out performance, thereby better ensuring the high-precision conductivity and high-quality electronic signal transmission performance of the platinum-plated semiconductor device products.

[0105] Although Comparative Examples 1 to 12 have a "four-combination" configuration, since the concentrations of their complexing agents, reducing agents and additives are lower or higher than the locked concentration range of the present invention, their appearance monitoring results can only reach medium, good or poor. The corrosion rate results of the nitric acid vapor test are 0.6 to 2.5%, which cannot reach the excellent level of 0.0% of the embodiment of the present invention. The roughness of the platinum coating is in a relatively rough range of 234 to 241 nm, which is very different from the 182 to 186 nm of Examples 19 to 27 of the present invention. The weight difference results before and after the friction and wear test range from 1.5 to 2.9 mg, which is far higher than 0.6 to 0.8 mg of Examples 19 to 27 of the present invention.

[0106] Comparative Examples 13 to 19, which are representative of the existing platinum electroplating technology, did not completely solve the micro pinholes and micro cracks in the platinum coating, resulting in defects in the appearance inspection results. The evaluation results were all poor, which was reflected in the results of the nitric acid vapor test, with a corrosion rate of 1.7 to 4.1%; further, the roughness of the platinum coating was 239 to 255 nm, which was consistent with the result of the uneven distribution of the platinum film thickness; the weight difference before and after the friction and wear test was 2.6 to 3.3 mg. The results of the appearance inspection, nitric acid vapor test, platinum coating roughness and friction and wear test further confirmed the problems of micro pinholes and micro cracks in the prior art.

[0107] In addition, although the preparation method provided in Comparative Example 20 solves the problems of micro pinholes and micro cracks existing in the chemical platinum plating layer, since the formula of its platinum chemical plating solution does not have the "four combinations" of the present invention, the weight difference before and after the friction and wear test is 1.3 mg. Although it has better results compared with Comparative Examples 13 to 19, it is quite different from 0.6 to 0.8 mg of Examples 19 to 27 of the present invention. As a result, the semiconductor electronic component products prepared by all the comparative examples described in Table 20 are difficult to meet the high-performance market demand for semiconductor electronic component products with excellent pluggability, high corrosion resistance, high-precision conductivity and high-quality electronic signal transmission performance.

[0108] The test results of the average resistance difference before and after the nitric acid vapor test and the average resistance difference before and after the plug-in test of the platinum-plated electronic circuit boards obtained in Examples 19 to 27 and Comparative Examples 1 to 20 are shown in Table 21.

[0109] Table 21

[0110] It can be seen from Table 21 that according to the criterion of the average difference in resistance before and after the nitric acid vapor test and the plug-in test of the platinum-plated electronic circuit board, the judgment results of Examples 19 to 27 of the present invention are excellent; the platinum-plated layer has excellent friction resistance, which provides an important preparation method for high-performance plug-in performance electronic materials required by high-end semiconductor electronic components; the platinum electroplating solution technology of the present invention can meet the market demand for the production of semiconductor electronic component products with high corrosion resistance, excellent plug-in performance, high-precision conductivity and high-quality electronic signal transmission performance.

[0111] Although Comparative Examples 1 to 12 have a "four-combination", since the concentrations of the complexing agent, the reducing agent and the additive are lower or higher than the locked concentration range of the present invention, the average resistance difference before and after the nitric acid vapor test is 0.79 to 0.97 mΩ, which is only good, and is far from the experimental result of 0.22 to 0.26 mΩ of the present invention. The average resistance difference before and after the platinum plating plug-in test is 0.95 to 2.15 mΩ, which is far less than the experimental result of 0.22 to 0.27 mΩ of the present invention.

[0112] Comparative Examples 13 to 19, which are representative of the existing platinum electroplating technology, did not completely solve the micro-pinholes and micro-cracks in the platinum coating, resulting in an average resistance difference of 2.31 to 7.25 mΩ before and after the nitric acid vapor corrosion test, which was unqualified and very different from the experimental result of 0.22 to 0.26 mΩ of the present invention; similarly, the average resistance difference of the platinum coating before and after the plug-in test was 5.31 to 9.36 mΩ, which was far less than the excellent experimental result of 0.22 to 0.26 mΩ of the present invention.

[0113] In addition, although the preparation method provided in Comparative Example 20 solves the problems of micro pinholes and micro cracks in the platinum coating, since the formula of its electroplating solution does not have the "four combinations" described in the present invention, its average resistance difference before and after the nitric acid vapor corrosion test is 0.83 mΩ, which can only reach good, which is a certain gap compared with the experimental results of 0.22~0.26 mΩ of the present invention; similarly, the average resistance difference before and after the platinum coating plug-in test is 1.25 mΩ, which is evaluated as unqualified, far less than the excellent experimental results of 0.22~0.27 mΩ of the present invention.

[0114] In summary, if the components of the platinum chemical plating solution provided by the present invention can meet the "four combinations", the concentration requirements of ethylenediamine sulfate, thiourea dioxide, malonic acid and platinum salt PEP (in terms of Pt), then the semiconductor electronic component product with a nanostructure of the chemically plated platinum layer has excellent uniform distribution, morphology, density and friction resistance, and can meet the production of semiconductor electronic component products with high corrosion resistance, excellent pluggability, high-precision conductivity and high-quality electronic signal transmission performance; on the contrary, if the components of the platinum chemical plating solution of Comparative Examples 1 to 20 fail to meet the "four components", the comprehensive performance of the platinum coating is significantly different from that of the present invention.

[0115] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A platinum chemical plating solution, characterized in that: The method comprises the following raw materials: 0.5-10.0 g / L of platinum salt PEP, 2.1-10.0 g / L of ethylenediamine sulfate, 1.2-8.9 g / L of malonic acid, 5-50 g / L of ammonium acetate, 1.2-9.2 g / L of thiourea dioxide, and the remainder is ultrapure water and ammonia water; the pH value of the solution is adjusted to 7.0 by using ammonia water; The structure of platinum salt PEP is shown in formula (1): Formula (1).

2. The platinum chemical plating solution according to claim 1, characterized in that The concentration of ethylenediamine sulfate was 6.1 g / L.

3. The platinum chemical plating solution according to claim 1, characterized in that The concentration of thiourea dioxide was 5.2 g / L.

4. The platinum chemical plating solution according to claim 1, characterized in that The concentration of malonic acid was 4.9 g / L.

5. A method for preparing the platinum chemical plating solution according to any one of claims 1 to 4, characterized in that: The steps include: (1) Preparation of starter solution A: Based on the final concentration of each component in the platinum chemical plating solution, ethylenediamine sulfate, ammonium acetate and platinum salt PEP are completely dissolved in an appropriate amount of ultrapure water under heating and stirring conditions, and the pH value of the solution is adjusted to 7 with ammonia water to obtain starter solution A; (2) Preparation of starter solution B: Based on the final concentration of each component in the platinum chemical plating solution, completely dissolve thiourea dioxide in an appropriate amount of ultrapure water under heating and stirring conditions, adjust the pH value of the solution to 7, and then add malonic acid to adjust the pH value of the solution to 7 to obtain starter solution B; (3) Compounding: Add the pre-bottle liquid B to the pre-bottle liquid A, mix well, and test the solution pH to 7. Use ultrapure water to make up the volume. During chemical plating, adjust the solution pH to 10.0 to obtain a platinum chemical plating solution.

6. The preparation method according to claim 5, characterized in that The heating and stirring conditions were: 50°C and 100 rpm.

7. A method for preparing a coating using the platinum chemical plating solution according to claim 1, characterized in that: The steps include: S1. Degreasing and acid activation treatment of the semiconductor electronic components to be processed; S2. Select the corresponding plating conditions according to the plating area and form of the plated part, and the solution temperature is 50~60 ℃; S3. During the plating process, an automatic analyzer is used to detect the concentration of platinum salt, thiourea dioxide concentration, and pH in the platinum chemical plating solution. Based on the difference between the test result and the solution control standard value, a linked automatic replenishing device is used to quantitatively add platinum salt PEP solution, thiourea dioxide, or pH adjuster; S4. After reaching the target coating thickness, stop plating to form a coating on the semiconductor electronic component.

8. The method according to claim 7, characterized in that During the plating process, the initial pH value of the platinum chemical plating solution is 7.

0. After the semiconductor device is placed in the plating solution, the pH value is detected in real time to control the pH value range to 9.5-10.5, so that thiourea dioxide is promoted to reduce Pt (II) to Pt (0) under the pH conditions. The pH value is controlled based on the real-time test results. Taking pH 10.0 as the standard, 0.1 mol / L sodium hydroxide solution is automatically added to maintain the pH of the plating solution at the standard value of 10.

9. Use of the platinum chemical plating solution according to claim 1 in the preparation of semiconductor device electronic products.

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