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The purpose of this paper is to introduce a new copper electroplating formula which is able to fill blind microvias (BVHs) and through holes (THs) at one process through a direct current (DC) plating method.

Test boards of printed circuit board (PCB) fragments with BVHs and THs for filling plating are designed. The filling plating is conducted in a DC plating device, and the filling processes and influence factors on filling effect of BVHs and THs are investigated. Dimple depths, surface copper thickness, thermal shock and thermal cycle test are applied to characterize filling effect and reliability. In addition, to overcome thickness, increase of copper on board surface during filling plating of BVHs and THs, a simple process called pattern plating, is put forwarded; a four-layered PCB with surface copper thickness less than 12 μm is successfully produced.

The filling plating with the new copper electroplating formula is potential to replace the conventional filling process of BVHs and THs of PCB and, most importantly, the problem of thickness increase of copper on board surface after filling process is overcome if a pattern plating process is applied.

The dimple depth of BVHs and THs after filling plating is not small enough, though it meets the requirements, and the smallest diameter and largest depth of holes studied are 75 and 200 μm, respectively. Hence, the possibility for filling holes of much more small in diameter and large in depth with the plating formula should be further studied.

The paper introduces a new copper electroplating formula which achieves BVHs and THs filling at one process through a DC plating method. It overall reduces production processes and improved reliability of products resulting in production cost saving and production efficiency improvement.

This paper aims to propose a modified full-additive method (MFAM) to fabricate fine copper lines for high density interconnection (HDI) printed circuit boards (PCBs). In addition, the surface of the fine copper lines is treated with a brown oxidation process to obtain good adhesion between the copper and the dielectric resin.

Fine copper lines fabricated by MFAM were observed to evaluate the undercut quality, in comparison to undercut quality of copper lines fabricated by the semi-additive method and the subtractive method. The effect of the thickness of the dry film on the quality of the copper plating was investigated to obtain the regular shape of fine lines. The fine copper lines treated with the brown oxidation process were also examined to generate a coarse surface microstructure to improve the adhesion between the copper and the dielectric resin. The cross section and surface of as-fabricated fine copper lines were characterized using an optical microscope, a scanning electron microscope and an atomic force microscope.

MFAM has the potential to fabricate high-performance fine copper lines for HDI PCBs. Undercut of as-fabricated fine copper lines could be prevented to meet the design requirement of impedance. In addition, fine copper lines exhibit enough adhesive force to laminate with dielectric resin after the brown oxidation process.

MFAM, with the advantages of high efficiency and being a facile process, is developed to fabricate high-quality fine copper lines for industrial HDI PCB manufacture.

The purpose of this paper is to study an electrolytic etching method to prepare fine lines on printed circuit board (PCB). And the influence of organics on the side corrosion protection of PCB fine lines during electrolytic etching is studied in detail.

In this paper, the etching factor of PCB fine lines produced by new method and the traditional method was analyzed by the metallographic microscope. In addition, field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to study the inhibition of undercut of the four organometallic corrosion inhibitors with 2,5-dimercapto-1,3,4-thiadiazole, benzotriazole, l-phenylalanine and l-tryptophan in the electrolytic etching process.

The SEM results show that corrosion inhibitors can greatly inhibit undercut of PCB fine lines during electrolytic etching process. XPS results indicate that N and S atoms on corrosion inhibitors can form covalent bonds with copper during electrolytic etching process, which can be adsorbed on sidewall of PCB fine lines to form a dense protective film, thereby inhibiting undercut of PCB fine lines. Quantum chemical calculations show that four corrosion inhibitor molecules tend to be parallel to copper surface and adsorb on copper surface in an optimal form. COMSOL Multiphysics simulation revealed that there is a significant difference in the amount of corrosion inhibitor adsorbed on sidewall of the fine line and the etching area.

As a clean production technology, electrolytic etching method has a good development indicator for the production of high-quality fine lines in PCB industry in the future. And it is of great significance in saving resources and reducing environmental pollution.

This paper aims to develop an ideal technique for the preparation of print circuit boards (PCBs) with ladder conductive lines on practical industrial process lines.

First, the raw materials of ladder copper-clad laminates were prepared by plating double-sided copper-clad laminates with vertical plating line. Second, etching compensation experiments were designed and conducted to set up the relationships between etching compensation and width of conductive lines on ladder line print circuit boards (LLPCBs). Third, to evaluate the process technique for the preparation of LLPCBs through etching compensation, verification experiments were designed and conducted on a practical industrial process line, and the quality of lines on LLPCBs was observed and evaluated.

Under the judgment of the quality of conductive lines on LLPCBs as well as the feasibility with a practical industrial process line, the process technique for the preparation of LLPCBs with etching compensation is a simple and reliable method which has the potential to be applied in the industry.

It is the first successful report of a new method that produces LLPCBs with etching compensation and has the potential to be applied in the industry.

The purpose of this study is to develop a novel approach to designing locally programmed multi-material distribution in a three-dimensional (3D) model, with the goal of producing a biomimetic robot that could mimic the locomotion of living organisms.

A voxelized representation is used to design the multi-material digital model and the material distribution in the model is optimized with the aims of mimicking the deflection dynamics of a real-life biological structure (i.e. inchworms) during its locomotion and achieving smooth deflection between adjacent regions. The design is validated post-fabrication by comparing the bending profiles of the printed robot with the deflection reference images of the real-life organism.

The proposed design framework in this study provides a foundation for multi-material multi-functional design for biomimicry and a wide range of applications in the manufacturing field and many other fields such as robotics and biomedical fields. The final optimized material design was 3D printed using a novel multi-material additive manufacturing method, magnetic field-assisted projection stereolithography. From the experimental tests, it was observed that the deflection curve and the deflection gradient of the printed robot within the adjacent regions of the body agreed well with the profiles taken from the real-life inchworm.

This paper presents a voxelized digital representation of the material distribution in printed parts, allowing spatially varied programming of material properties. The incorporation of reference images from living organisms into the design approach is a novel approach to transform image domain knowledge into the domain of engineering mechanical and material properties. Furthermore, the novel multi-material distribution design approach was validated through designing, 3D printing and prototyping an inchworm-inspired soft robot, which showed superior locomotion capability by mimicking the observed locomotion of the real inchworm.