Cleaning agent composition as well as preparation method and cleaning method thereof

Abstract

The invention relates to a cleaning agent composition and a preparation method and a cleaning method thereof in the technical field of substrate cleaning, and the cleaning agent composition comprises trans-1, 2-dichloroethylene, 1, 1, 2, 2-tetrafluoroethyl-2, 2, 2-trifluoroethyl ether and fluorine-containing carboxylic acid. The cleaning agent composition has a good scaling powder cleaning effect and can effectively reduce the possibility that the surface of the substrate is corroded.

Description

Technical Field

[0001] This application relates to the field of substrate cleaning technology, and in particular to a cleaning agent composition, its preparation method, and cleaning method. Background Technology

[0002] Direct Bond Copper (DBC) ceramic substrates possess the high thermal conductivity, high electrical insulation, high mechanical strength, and low expansion properties of ceramics, while also having the high electrical conductivity and excellent solderability of oxygen-free copper. Furthermore, they can be etched with various patterns like PCB circuit boards, making them an important electronic packaging material, especially in power modules (IGBTs) and integrated power electronic modules.

[0003] The DBC substrate undergoes a series of processes including wafer mounting, vacuum reflow soldering, wafer bonding, pin mounting, cleaning, vacuum reflow soldering, sealing, ultrasonic welding, canning, curing, and testing to form IGBT modules. During the vacuum reflow soldering process, flux can scatter from the solder paste and adhere to the DBC substrate as residue. Therefore, the DBC substrate needs to be cleaned to remove flux residue. Currently, mainstream flux cleaners are solvent-based. Solvent cleaners mainly include halogenated hydrocarbons (chlorinated hydrocarbons, brominated hydrocarbons, fluorinated hydrocarbons), petroleum-based solvents, alcohols, ethers, glycol esters, and siloxanes. Although existing solvent-based cleaners meet the requirements for flux removal, they inevitably form an oxide layer on the DBC substrate surface during cleaning, leading to blackening or even corrosion. Furthermore, current semi-aqueous cleaners have long process flows and high operating costs, while water-based cleaners have poor flux removal effects. Summary of the Invention

[0004] In view of the problems existing in the background art, this application provides a cleaning agent composition and its preparation method and cleaning method. The cleaning agent composition has a good flux cleaning effect and can effectively reduce the possibility of substrate surface corrosion.

[0005] According to a first aspect of the invention, a cleaning composition is provided, comprising trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, and a fluorinated carboxylic acid, wherein the fluorinated carboxylic acid is selected from at least one of hexafluoropropylene oxide dimer carboxylic acid and hexafluoropropylene oxide trimer carboxylic acid.

[0006] In some embodiments of the present invention, the contents of each component of the cleaning agent composition, by weight, are as follows:

[0007] 50-70 parts of trans-1,2-dichloroethylene;

[0008] 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether;

[0009] 1-3 parts of fluorinated carboxylic acids.

[0010] In some embodiments of the present invention, the contents of each component of the cleaning agent composition, by weight, are as follows:

[0011] 50-70 parts of trans-1,2-dichloroethylene;

[0012] 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether;

[0013] 1-3 parts of hexafluoropropylene oxide dimer carboxylic acid.

[0014] In some embodiments of the present invention, the contents of each component of the cleaning agent composition are as follows, by weight:

[0015] 50-70 parts of trans-1,2-dichloroethylene;

[0016] 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether;

[0017] 1-3 parts of hexafluoropropylene oxide trimer carboxylic acid.

[0018] According to a second aspect of the present invention, a method for preparing the above-described cleaning agent composition is provided, comprising the following steps: adding trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and a fluorinated carboxylic acid into a container and stirring until homogeneous to obtain the cleaning agent composition.

[0019] In some embodiments of the present invention, the trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and fluorinated carboxylic acid are stirred and mixed evenly at room temperature.

[0020] In some embodiments of the present invention, the stirring time is 4-6 minutes.

[0021] According to a third aspect of the present invention, a method for cleaning a DBC substrate using the above-described cleaning agent composition is provided, comprising the following steps: placing the DBC substrate in the cleaning agent composition for cleaning, and then placing the cleaned DBC substrate in a rinsing agent for rinsing.

[0022] In some embodiments of the present invention, the DBC substrate is placed in the cleaning agent composition and ultrasonically treated at 35-45°C for 25-35 minutes.

[0023] The cleaning agent composition of this invention uses a mixture of trans-1,2-dichloroethylene (t-DCE) and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (HFE-347), with the addition of certain fluorinated carboxylic acids such as hexafluoropropylene oxide dimer carboxylic acid and / or hexafluoropropylene oxide trimer carboxylic acid as additives. The mixture of HFE-347 and t-DCE yields a composition without flash point. t-DCE has a good cleaning effect on flux. The fluorinated carboxylic acids react with metal oxides, rapidly removing them, resulting in no corrosion on the surface of the DBC substrate after cleaning. Furthermore, the cleaning agent composition does not contain CFCs or HCFCs, and is not a product phased out by the state, greatly reducing the impact on the ecological environment and making it more environmentally friendly. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application.

[0025] Figure 1 This is a photograph of the DBC substrate in the test example of the present invention before cleaning;

[0026] Figure 2 This is a photograph of the DBC substrate after cleaning with the cleaning agent of Example 1;

[0027] Figure 3 The image shows the DBC substrate after cleaning with the cleaning agent used in Comparative Example 1.

[0028] Figure 4 This is a photograph of the DBC substrate after cleaning with the cleaning agent used in Comparative Example 8. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art will readily identify several non-critical parameters that can be varied or modified without yielding substantially the same results.

[0030] Unless otherwise specified, the techniques or conditions described in the examples shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels. Unless otherwise specified, the experimental methods in the following examples are conventional methods. Unless otherwise specified, the experimental materials used in the following examples are all commercially available products.

[0031] This application discloses a cleaning agent composition comprising trans-1,2-dichloroethylene (t-DCE), 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (HFE-347), and a fluorinated carboxylic acid, wherein the fluorinated carboxylic acid is selected from at least one of hexafluoropropylene oxide dimer carboxylic acid and hexafluoropropylene oxide trimer carboxylic acid.

[0032] The cleaning agent composition of the present invention uses a mixture of t-DCE and HFE-347, with the addition of a certain amount of fluorinated carboxylic acid as an additive. Among them, t-DCE has a good cleaning effect on flux, and the fluorinated carboxylic acid is miscible with HFE-347. Its terminal carboxylic acid can react with copper oxide on the surface of DBC substrate, which can quickly remove metal oxides and form a protective film on the surface of DBC substrate, protecting the copper foil on the surface of DBC substrate from further oxidation. Thus, while ensuring the cleaning effect of flux on DBC substrate, it can effectively reduce the possibility of substrate surface corrosion.

[0033] Furthermore, since t-DCE itself has a low flash point of -11°C, it cannot be used directly. By mixing HFE-347 with t-DCE, the flash point of the composition can be increased or even a composition with no flash point can be obtained, effectively overcoming the problem of the low flash point of t-DCE. Moreover, the cleaning agent composition of the present invention does not contain CFCs and HCFCs, and selects components with low GWP (Global Warming Potential) and zero ODP (Ozone Depletion Potential) as the main components, which greatly reduces the impact on the ecological environment and makes it more environmentally friendly.

[0034] In some embodiments of the present invention, the contents of each component of the cleaning agent composition are as follows, by weight: 50-70 parts of trans-1,2-dichloroethylene; 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; and 1-3 parts of fluorinated carboxylic acid.

[0035] In this embodiment, by using hexafluoropropylene oxide dimer carboxylic acid and / or hexafluoropropylene oxide trimer carboxylic acid as additives, metal oxides on the substrate surface can be quickly removed, further effectively reducing or even preventing corrosion of the DBC substrate surface and improving the protection of the DBC substrate.

[0036] In some embodiments of the present invention, hexafluoropropylene oxide dimer carboxylic acid can be obtained by purifying hexafluoropropylene oxide dimer acyl fluoride after hydrolysis, and hexafluoropropylene oxide dimer acyl fluoride can be prepared by the method in patent CN108264458A.

[0037] In some embodiments of the present invention, hexafluoropropylene oxide trimer carboxylic acid can be prepared by the following steps:

[0038] A polar aprotic solvent is mixed with a composite catalyst initiator and a chain transfer inhibitor, and hexafluoropropylene oxide is added to the system to react. The temperature in the reaction system is controlled at -20℃ to -10℃. After the reaction is completed, the crude product is separated by liquid separation and distillation to obtain hexafluoropropylene oxide trimer.

[0039] Furthermore, the polar aprotic solvent may be selected from one or more of tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, acetonitrile, propionitrile, and tetrahydrofuran.

[0040] The composite catalytic initiator is a mixture of hexafluoropropylene oxide dimer alkoxide and alkali metal fluoride, wherein the molar ratio of hexafluoropropylene oxide dimer alkoxide to alkali metal fluoride is 1:(1-10); the hexafluoropropylene oxide dimer alkoxide is selected from one or more of lithium hexafluoropropylene oxide dimer alkoxide, sodium hexafluoropropylene oxide dimer alkoxide, potassium hexafluoropropylene oxide dimer alkoxide, and cesium hexafluoropropylene oxide dimer alkoxide; the alkali metal fluoride is selected from one or more of lithium fluoride, sodium fluoride, potassium fluoride, and cesium fluoride.

[0041] The chain transfer inhibitor is a perfluorocarboxylic acid, preferably a straight-chain or branched perfluorocarboxylic acid with ≤10 carbon atoms, more preferably selected from one or more of trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid, perfluorohexanoic acid and perfluorooctanoic acid.

[0042] Furthermore, the mass ratio of chain transfer inhibitor to hexafluoropropylene oxide is 1:(50-500); the molar ratio of composite catalyst initiator to hexafluoropropylene oxide is 1:(10-60); the mass ratio of polar aprotic solvent to hexafluoropropylene oxide is 1:(5-10); the hexafluoropropylene oxide is added by bubbling through a gas flow meter, with a feeding rate of 100-800 sccm, preferably 300-400 sccm.

[0043] In some embodiments of the present invention, the contents of each component of the cleaning agent composition are as follows, by weight: 50-70 parts of trans-1,2-dichloroethylene; 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; and 1-3 parts of hexafluoropropylene oxide dimer carboxylic acid.

[0044] In some embodiments of the present invention, the contents of each component of the cleaning agent composition are as follows, by weight: 50-70 parts of trans-1,2-dichloroethylene; 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; and 1-3 parts of hexafluoropropylene oxide trimer carboxylic acid.

[0045] In this embodiment, by weight, 50-70 parts of trans-1,2-dichloroethylene, 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, and 1-3 parts of fluorinated carboxylic acid are mixed together. This combination provides better cleaning effect on flux and better protection for the DBC substrate. It can not only thoroughly clean away the flux, but also remove the metal oxides on the substrate surface. The cleaned substrate surface shows no corrosion, further enhancing the protection of the DBC substrate.

[0046] Furthermore, by weight, the contents of each component in the cleaning agent composition are as follows: trans-1,2-dichloroethylene accounts for 60 parts; 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl accounts for 37 parts; and hexafluoropropylene oxide dimer carboxylic acid and / or hexafluoropropylene oxide trimer carboxylic acid accounts for 3 parts.

[0047] This application also discloses a method for preparing the above-mentioned cleaning agent composition, comprising the following steps:

[0048] Trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, and fluorinated carboxylic acid are added to a container in the specified weight proportions and stirred until homogeneous to obtain a cleaning agent composition.

[0049] In some embodiments of the present invention, trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and fluorinated carboxylic acid are stirred and mixed evenly at room temperature.

[0050] It should be understood that room temperature refers to the temperature of the indoor environment, and its specific range can vary depending on different standards and needs, such as a temperature between 18 and 26°C.

[0051] Furthermore, the trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and fluorinated carboxylic acid are stirred and mixed at room temperature for 4-6 minutes.

[0052] This application also discloses a method for cleaning a DBC substrate using the above-mentioned cleaning agent composition, comprising the following steps:

[0053] The DBC substrate is cleaned by placing it in a cleaning agent composition to remove flux and metal oxides from the surface of the DBC substrate. Then, the cleaned DBC substrate is rinsed in a rinsing agent to remove any residual cleaning agent composition from the surface of the DBC substrate.

[0054] In some embodiments of the present invention, the DBC substrate is ultrasonically treated in a cleaning agent composition at 35-45°C for 25-35 minutes.

[0055] In some embodiments of the present invention, the cleaned DBC substrate is subjected to ultrasonic treatment in a rinsing agent at room temperature for 5 minutes.

[0056] Furthermore, the rinsing agent is HFE-347.

[0057] The cleaning agent composition of the present invention can not only thoroughly clean the flux on the surface of the DBC substrate and prevent copper oxidation, but also has a simpler and more efficient cleaning process compared to semi-aqueous cleaning agents, and a superior cleaning effect on flux compared to water-based cleaning agents.

[0058] The present invention also provides the following embodiments, comparative examples, and test cases.

[0059] Example 1

[0060] Add t-DCE, HFE-347 and hexafluoropropylene oxide trimer carboxylic acid to a beaker and stir at room temperature for 5 minutes to obtain a mixed cleaning agent component. The weight ratio of t-DCE, HFE-347 and hexafluoropropylene oxide trimer carboxylic acid is 50:48:2.

[0061] Examples 2-8 and Comparative Examples 1-8 used the same preparation process as Example 1, the only difference being the different components and weight ratios of the cleaning agent.

[0062] The specific components and proportions of Examples 2-8 and Comparative Examples 1-8 of this invention are detailed in Table 1 below.

[0063] Table 1. Composition and weight ratio of cleaning agent

[0064] t-DCE HFE-347 Proportion of carboxylic acids Types of carboxylic acids Example 1 50 48 2 Hexafluoropropylene oxide trimer carboxylic acid Example 2 55 44 1 Hexafluoropropylene oxide trimer carboxylic acid Example 3 60 37 3 Hexafluoropropylene oxide trimer carboxylic acid Example 4 65 34 1 Hexafluoropropylene oxide trimer carboxylic acid Example 5 70 28 2 Hexafluoropropylene oxide trimer carboxylic acid Example 6 50 48 2 Hexafluoropropylene oxide dimer carboxylic acid Example 7 60 37 3 Hexafluoropropylene oxide dimer carboxylic acid Example 8 70 28 2 Hexafluoropropylene oxide dimer carboxylic acid Comparative Example 1 40 60 0 No added carboxylic acid Comparative Example 2 65 35 0 No added carboxylic acid Comparative Example 3 75 23 2 Hexafluoropropylene oxide trimer carboxylic acid Comparative Example 4 90 10 0 No added carboxylic acid Comparative Example 5 50 45 5 Hexafluoropropylene oxide trimer carboxylic acid Comparative Example 6 50 45 5 Hexafluoropropylene oxide dimer carboxylic acid Comparative Example 7 55 44 1 acetic acid Comparative Example 8 55 44 1 Trifluoroacetic acid

[0065] Test case

[0066] 1. The flash points of each example and comparative sample were tested according to the national standard GB / T 21775-2008 "Flash Point Measurement Closed Cup Equilibrium Method".

[0067] 2. Treatment of DBC substrates by various embodiments and comparative samples: DBC substrate cleaning process: The DBC substrate was placed in a mixed cleaning agent and ultrasonically treated at 40°C for 30 minutes, and the surface phenomenon was observed; DBC substrate rinsing process: The cleaned DBC substrate was ultrasonically treated at room temperature in a rinsing agent, which was HFE-347, for 5 minutes.

[0068] Test results:

[0069] Table 2. Flash point of cleaning agent and cleaning effect on DBC substrate

[0070]

[0071] Figure 1This is a photo of the DBC substrate before cleaning, such as... Figure 1 As shown, flux was present on the surface of the DBC substrates in each embodiment and comparative example before cleaning.

[0072] Figure 2 The image shows the DBC substrate after cleaning with the cleaning agent of Example 1. The cleaning agent compositions of Examples 1-8 thoroughly cleaned the flux and completely removed the metal oxides on the substrate surface. The DBC substrate remained intact and showed no further corrosion.

[0073] Figure 3 The image shows the DBC substrate after cleaning with the cleaning agent of Comparative Example 1. Comparative Example 1 shows some flux residue and corrosion-induced blackening, indicating that the metal oxides on the substrate surface could not be removed. The t-DCE content was too low, resulting in incomplete flux cleaning. The absence of fluorinated carboxylic acid led to corrosion-induced blackening, indicating the formation of copper oxide.

[0074] Corrosion occurred in Comparative Example 2 because no fluorinated carboxylic acid was added.

[0075] Comparative Example 3 showed satisfactory cleaning results, but its t-DCE content was too high, causing the cleaning agent composition to have a flash point and failing to meet the usage requirements.

[0076] Comparative Example 4 exhibits corrosion and a flash point, failing to meet usage requirements.

[0077] In Comparative Examples 5 and 6, due to excessively high levels of added hexafluoropropylene oxide trimer carboxylic acid and hexafluoropropylene oxide dimer carboxylic acid, some hexafluoropropylene oxide trimer carboxylic acid and hexafluoropropylene oxide dimer carboxylic acid remained after rinsing and could not be removed.

[0078] Figure 4 The image shows the DBC substrate after cleaning with the cleaning agent of Comparative Example 8. Comparative Examples 7 and 8 are more acidic due to the addition of acetic acid or trifluoroacetic acid. Although the flux and metal oxides were thoroughly cleaned, some parts of the DBC substrate were further corroded.

[0079] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A cleaning agent composition, characterized in that, It includes trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, and fluorinated carboxylic acids, wherein the fluorinated carboxylic acid is selected from at least one of hexafluoropropylene oxide dimer carboxylic acid and hexafluoropropylene oxide trimer carboxylic acid.

2. The cleaning agent composition according to claim 1, characterized in that, The components of the cleaning agent composition are present in the following proportions by weight: 50-70 parts of trans-1,2-dichloroethylene; 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; 1-3 parts of fluorinated carboxylic acids.

3. The cleaning agent composition according to claim 1, characterized in that, The components of the cleaning agent composition are present in the following proportions by weight: 50-70 parts of trans-1,2-dichloroethylene; 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; 1-3 parts of hexafluoropropylene oxide dimer carboxylic acid.

4. The cleaning agent composition according to claim 1, characterized in that, The components of the cleaning agent composition are present in the following proportions by weight: 50-70 parts of trans-1,2-dichloroethylene; 25-48 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether; 1-3 parts of hexafluoropropylene oxide trimer carboxylic acid.

5. A method for preparing a cleaning agent composition according to any one of claims 1-4, characterized in that, Includes the following steps: Trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, and fluorinated carboxylic acid are added to a container and stirred until homogeneous to obtain the cleaning agent composition.

6. The preparation method according to claim 5, characterized in that, The trans-1,2-dichloroethylene, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and fluorinated carboxylic acid were stirred and mixed evenly at room temperature.

7. A method for cleaning a DBC substrate using a cleaning agent composition as described in any one of claims 1-4, characterized in that, Includes the following steps: The DBC substrate is placed in the cleaning agent composition for cleaning, and then the cleaned DBC substrate is placed in the rinsing agent for rinsing.

8. The method according to claim 7, characterized in that, The DBC substrate is placed in the cleaning agent composition and ultrasonically treated at 35-45°C for 25-35 minutes.

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