METHOD FOR IMPROVING THE SOLDERABILITY OF A GALVANIZED BASE PLATE

Abstract

Method (100) for producing a solderable part, the method comprising - Providing a semi-finished product of a solderable part (110); - Providing an intermediate product by carrying out a processing of the pre-product (120); and - Providing a final product by carrying out a washing of the intermediate product using deionized water to which a predetermined amount of a surfactant is added (130).

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to a method for producing a solderable part, in particular to a method for improving the solderability of a galvanized base plate or other solderable parts. BACKGROUND

[0002] Water spots are a well-known problem that occurs after electroplating. These spots are also known to cause various soldering problems. Countless batches of electroplated base plates are rejected or blocked due to these defects, resulting in enormous effort and scrap. The only preventative measures are a very elaborate washing and drying process, 100% visual inspection, and, if spots remain on the surface, reworking the base plates. All of these measures are time-consuming, expensive, and tie up manpower.

[0003] The final wash bath in an electroplating process typically contains highly purified water to minimize the amount of stains, followed by an intensive drying process. Nevertheless, stains are frequently found on the base plate, which, if undetected, can lead to rejects at the supplier or yield losses due to soldering problems at the customer's site.

[0004] Document US 2015 / 0208499 A1 describes a ceramic printed circuit board made of laser-etched copper and its manufacturing process. The process includes providing a ceramic substrate, laser engraving on one surface of the ceramic substrate to form a circuit pattern from a variety of groove structures, roughening and activating the surface of the ceramic substrate by washing it with a roughening and activating solution, and depositing a metal layer onto the groove structures to form a conductive loop defined by the circuit pattern.

[0005] Publication US 2013 / 0292254 A1 describes a method for cleaning a lip seal or cup bottom of an electroplating device by removing metal deposits that have accumulated during previous electroplating processes.

[0006] For these and other reasons, there is a need for the present disclosure. SUMMARY

[0007] Investigations by the inventors of the present disclosure have shown that adding specific amounts of surfactants to the water that forms the spots enables soldering without soldering problems. When these surfactants are added to the final wash bath in an electroplating line, any spots that arise can be classified as non-critical, thereby reducing effort, scrap, and yield losses.

[0008] One aspect of the present disclosure relates to a method for providing a solderable part, wherein the method comprises providing a pre-product of a solderable part, providing an intermediate product by carrying out a processing of the pre-product, and providing a final product by carrying out a washing of the intermediate product using deionized water to which a predetermined amount of a surfactant is added.

[0009] According to one embodiment of the method, the surfactant is an anionic surfactant such as sodium dodecyl sulfate.

[0010] According to another embodiment of the method, the surfactant comprises a nonionic surfactant such as polyethylene glycol. In one example, the amount of polyethylene glycol added to the deionized water is greater than 0.1 g / L.

[0011] According to one embodiment of the method, the solderable part is a coated base plate, in particular a nickel-plated base plate. According to another example, the intermediate product is a base plate, in particular a bare copper base plate, the intermediate product is a nickel-plated copper base plate, and the final product is a washed nickel-plated copper base plate. According to a further example, the method comprises degreasing the base plate, washing the degreased base plate, etching the washed base plate, washing the etched base plate, activating the washed base plate, plating the activated base plate, washing the plated base plate, and drying the washed base plate. In yet another example, a surfactant is added only in the final washing step.

[0012] According to another embodiment of the method, the solderable part comprises one or more components consisting of a Direct Copper Bond (DCB), an Active Metal Braze (AMB), an Insulated Metal Substrate (IMS), a Metal Pin and a Conductor Frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings serve to further understand the embodiments and are an integral part of this description. The drawings illustrate embodiments and, together with the description, serve to explain the principles of these embodiments. Other embodiments and many of the intended advantages of the embodiments will be readily appreciated when they are better understood by reference to the following detailed description. Fig. Figure 1 shows a flowchart of a process for manufacturing a solderable part. Fig. Figure 2 shows a flowchart of an example of a process for manufacturing a solderable part, wherein the process is a complete process flow of electroplating a base plate. DESCRIPTION OF THE EXECUTION FORMS

[0014] The following detailed description refers to the accompanying drawings, which form part of this document and illustrate specific embodiments in which the disclosure can be practiced. In this context, directional terms such as "top," "bottom," "front," "back," "front," "back," etc., are used with reference to the orientation of the described figure(s). Since the components of the embodiments can be arranged in a number of different orientations, the directional terminology serves only for illustration and is in no way limiting. It is understood that other embodiments may be used and structural or logical modifications may be made without exceeding the scope of this disclosure.The following detailed description is therefore not to be understood in a limiting sense, and the scope of the present disclosure is defined by the attached claims.

[0015] It is understood that the features of the various exemplary embodiments described here can be combined with each other, unless expressly stated otherwise.

[0016] As used in this description, the terms "connected," "attached," "coupled," and / or "electrically connected / coupled" are not to be understood as requiring the elements or layers to be in direct contact with one another; intermediate elements or layers may be provided between the "connected," "attached," "coupled," and / or "electrically connected / coupled" elements. However, according to the disclosure, the above terms may also have the specific meaning that the elements or layers are in direct contact with one another, i.e., that no intermediate elements or layers are provided between the "connected," "attached," "connected," "coupled," and / or "electrically connected / coupled" elements.

[0017] Furthermore, the word "over," when used in reference to a part, element, or layer of material formed or arranged "over" a surface, can be used here to mean that the part, element, or layer of material is arranged (e.g., placed, formed, deposited, etc.) "indirectly on" the implied surface, with one or more additional parts, elements, or layers positioned between the implied surface and the part, element, or layer of material. However, the word "over," when used in reference to a part, element, or layer of material formed or arranged "over" a surface, can also optionally have the specific meaning that the part, element, or layer of material is arranged (e.g., placed, formed, deposited, etc.) "directly," that is, in direct contact with the implied surface.

[0018] Where the terms "with," "containing," "including," or variations thereof are used in the detailed description or in the claims, these terms, like the term "comprehensive," are to be understood as comprehensive. That is to say, the terms "with," "containing," "including," "comprehensive," and the like used here are open terms that indicate the presence of certain elements or features but do not exclude additional elements or features. The articles "a," "an," and "the" include both the plural and the singular unless the context clearly indicates otherwise.

[0019] Furthermore, the word "exemplary" is used here to mean an example, instance, or illustration. Any aspect or design described here as "exemplary" is not necessarily to be understood as superior to other aspects or designs. Rather, the use of the word "exemplary" is intended to illustrate concepts in a concrete way. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." That is to say, unless otherwise stated or evident from the context, "X uses A or B" means any of the natural, inclusive permutations. That is, if X uses A, X uses B, or X uses both A and B, then "X uses A or B" is satisfied in each of the aforementioned cases.Furthermore, the articles “a” and “an”, as used in this application and the attached claims, can generally be interpreted as meaning “one or more”, unless otherwise specified or it is clear from the context that they refer to a sinusoidal shape. Likewise, “at least one of A and B” or the like generally means A or B or both A and B.

[0020] Furthermore, although a particular feature or aspect of an embodiment of the disclosure may only be disclosed in relation to one of several embodiments, such a feature or aspect may be combined with one or more other features or aspects of the other embodiments as may be desirable and advantageous for a given or particular application. Where the terms "comprise," "have," "with," or other variants thereof are used in the detailed description or in the claims, these terms are to be understood as comprehensive, similar to the term "comprise." Furthermore, it is to be understood that embodiments of the disclosure may be implemented in discrete circuits, semi-integrated circuits, or fully integrated circuits or programming means.The term "exemplary" should also be understood merely as an example and not as the best or optimal solution. It should also be noted that, for the sake of simplicity and better understanding, the features and / or elements presented here are shown with specific dimensions relative to each other, and that the actual dimensions may differ considerably from those shown here. DETAILED DESCRIPTION

[0021] Fig. Figure 1 shows a flowchart of a process for manufacturing a solderable part.

[0022] More precisely, the procedure comprises 100 according to Fig. 1 the provision of a pre-product of a solderable part (110), the provision of an intermediate product by carrying out a processing of the pre-product (120) and the provision of a final product by carrying out a washing of the intermediate product using deionized water to which a predetermined amount of a surfactant is added (130).

[0023] The solderable part can be, in particular, a plated base plate, especially a nickel-plated copper base plate. In this case, the intermediate product is a base plate, especially a bare copper base plate, the intermediate product is a nickel-plated copper base plate, and the final product is a washed nickel-plated copper base plate. An example of a process flow for nickel-plating a copper base plate is shown in Fig. 2 shown.

[0024] Fig. Figure 2 shows a flowchart of an example of a process for manufacturing a solderable part, wherein the process is a complete process flow of electroplating a base plate.

[0025] More precisely, such a procedure can be carried out in 200 according to Fig. 2 include degreasing the base plate 210, washing the degreased base plate 220, etching the washed base plate 230, washing the etched base plate 240, activating the washed base plate 250, plating the activated base plate 260, washing the plated base plate 270 and drying the washed base plate 280.

[0026] Process 200 therefore comprises three washing steps. Theoretically, it would be possible to add a surfactant to the deionized water in each of the three washing steps. However, it is only practical to do this in the last three washing steps.

[0027] Polyethylene glycol, for example, can be used as a surfactant. It has been shown that the amount of polyethylene glycol added to the deionized water is preferably greater than 0.1 g / L. Satisfactory results regarding the wettability of the base plate with solder can be achieved with higher concentrations.

[0028] The applicant conducted experiments using a so-called wetting balance. This type of wetting balance, known per se, is used to measure the vertical buoyancy forces and surface tension when a test specimen is immersed in a solder bath. The wetting force is converted into an analog signal by a sensor and plotted over time. Various components were added to the water, and the washing step was performed with each of these different mixtures. The results showed that the wettability of a nickel-plated base plate with a conventional solder improved significantly compared to a sample washed with only deionized water when surfactants such as polyethylene glycol or sodium dodecyl sulfate were added. This demonstrated that the effects of water stains on the soldering process could be reduced.

[0029] Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that a multitude of alternative and / or equivalent embodiments may be used in place of the specific embodiments shown and described without infringing the scope of this disclosure. This application is intended to cover all adaptations or variations of the embodiments described herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents.

Claims

[1] A method (100) for producing a solderable part, the method comprising - Providing a precursor of a solderable part (110); - providing an intermediate product by processing the preliminary product (120); and - Providing a final product by washing the intermediate product using deionized water to which a predetermined amount of a surfactant is added (130). [2] The method (100) of claim 1, wherein the surfactant comprises polyethylene glycol. [3] The method (100) of claim 2, wherein the amount of polyethylene glycol added to the deionized water is greater than 0.1 g / L. [4] The method (100) of any preceding claim, wherein the surfactant comprises sodium dodecyl sulfate. [5] Method (100) according to one of the preceding claims, wherein the solderable part is a plated base plate, in particular a nickel-plated base plate. [6] Method (100) according to claim 5, wherein the precursor product is a base plate, in particular a bare copper base plate, the intermediate product is a nickel-plated copper base plate, and the final product is a washed, nickel-plated copper base plate. [7] The method (200) of claim 6, comprising degreasing the base plate (210); Washing the degreased base plate (220); Etching the washed base plate (230); Washing the etched base plate (240); Activating the washed base plate (250); Electroplating the activated base plate (260); Washing the plated base plate (270); and Drying the washed base plate (280). [8] The method (200) of claim 7, wherein a surfactant is added only in the final washing step (270). [9] The method (100) of any one of claims 1 to 4, wherein the solderable part is one or more of Direct Copper Bond (DCB), Active Metal Braze (AMB), a metal pin, and a lead frame.

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