Enhancing Cost Efficiency and Reliability of Tantalum Capacitors through Advanced Anode Control Methods

?????V. Azbel Ph.D. Semiconductor Process Reliability Engineer Consultant

Abstract: This article is on the critical component of tantalum capacitor-anode, which contributes significantly to cost and reliability. The article proposes an additional control method for anode production, leveraging advanced virtual simulation tools and control algorithms. The proposed approach aims to reduce costs, enhance quality, and increase the reliability of tantalum capacitors, particularly in industries like aerospace, automotive, and medical. The integration of these methods into production processes promises stable and reliable manufacturing of tantalum capacitors and is reflected in the rising yield on the final test.

?Keywords: Tantalum capacitors, anode control, cost efficiency, reliability, virtual simulation, quality control, production optimization

?Reviews available in the literature about the prospects for the development of tantalum capacitors (TC) for the next 10 years, note an increasing need for them, due to their high capacitance and excellent reliability and stability in operating conditions, compared with ceramic and aluminum.

However, prices for tantalum capacitors are higher compared to other types of capacitors.

This is due to the cost of the tantalum powder and the complex and difficult manufacturing process involving sintering the tantalum powder and forming a dielectric oxide layer. These additional manufacturing steps add to the cost.

The most costly and responsible for reliability, the structural element of the TC- is considered to be the anode. see Fig.1.

. Fig.1 The diagram illustrates the impact of anode quality on the productivity, reliability, and cost of tantalum capacitors (insufficient quality leads to reduced productivity, reliability, and higher cost, and vice versa)

Despite the fact that the production of the anode is a complex multi-stage technological process, see Fig.2 and each subsequent stage depends on the previous one, its quality control is carried out only at the final stage of its manufacture, which does not guarantee quality in terms of parameter Direct leakage current

Fig. 2.?Technological process schema of tantalum capacitor anode manufacturing

?Reducing costs and improving reliability begins with reducing the cost of using powder, which is due to its quality, which depends on its manufacturer, and reducing losses due problem of the production process of sintering and formation anode.

?1. Control of powder quality: Today, the quality of the powder is controlled by the CAP and DCL values of the anode produced according to the technical parameters specified by the manufactory capacitors.

Two key parameters of the powder, which should ensure the stability of the electrical characteristics (acceptable values of CAP and DCL) of the anode, are the particle size distribution and their morphology, which is not guaranteed by the currently controlled values of its CAP and DCL.

For the production of reliable capacitors, with a similar design, in the current process, it is important to have a controlled and constant particle size distribution, from batch to batch, or when changing vendors, in order to achieve the stability of the electrical properties of the produced TCs.

?2. Improvement in control of the sintering process: The acceptability of the pellet after sintering, for the next step manufactory, is currently controlled by shrinkage, which doesn't guarantee the maintenance of the desired porous structure, average neck size, and defectiveness.

?3. Evaluation of aging processes: The reliability of the TC, which is verified during long-term tests, depends significantly on the stability of the electrical characteristics of the anode, first of all, DCL. Degradation of DCL, in such tests, is associated with the processes of irreversible changes in the structure of the anode, due to the aging process.

The possibility of evaluating aging processes directly on the finished anode will allow for avoiding the time and financial costs of using it, during the production of TC.

?4. Mechanical stability: Anodes must be mechanically stable in order to withstand mechanical loads during the manufacture and installation of the TC, as well as the temperature cycles and shock/vibration conditions that the TC is subjected to during operation.

?The decrease of risk above problems affecting the cost and reliability are proposed to be solved by introducing an additional method of control in the production of the anode,

The proposed method is widely used in powder metallurgy to analyze the porous structure of the material, which directly affects the electrical properties of the resulting tantalum capacitors.

Using of method will reduce the cost of production of TC and rise quality, especially for applications in industries such as aerospace, automotive, and medical, as well as increase the reliability of tantalum polymer capacitors, in which there is no possibility of healing the dielectric.

The technological parameters used (see Fig. 2), acting on the powder, leads to the construction of a porous composite material, which, under specific testing conditions, exhibits properties typical of an anode, such as CAP and DCL anode.

My approach includes the use of advanced virtual simulation tools and control algorithms that I have developed through scrupulous research and development. These methods allow the manufacturer of the capacitors to optimize the production process.

The technique and virtual program developed by me will help to reduce the cost, in spite of the introduction of an additional control method, and increase the reliability of an anode.

Using the characteristics obtained by the proposed method as process control parameters in SAP, you can define quality control procedures, record measurement results and analyze trends to ensure stable and reliable production of tantalum capacitors.