Effect of Copper Sulfate and Sulfuric Acid on Blind Hole Filling of HDI Circuit Boards by Electroplating

Abstract

Here, in a certain high density interconnect (HDI) printed circuit board, the effect of copper sulfate and sulfuric acid on the filling effect of a blind hole with a certain diameter and depth was investigated by making a blind hole using a CO2 laser drilling machine, filling the blind hole via electroplating by simulating the electroplating line in a Halin cell, and observing the cross-section of a micro blind hole after polishing using metallographic microscope, as well as the effect of hole filling, are evaluated. The results show that, under the conditions of a certain plating solution formula and electroplating parameters (current density and electroplating time), the sag degree decreases with the increase in the copper sulfate concentration. When the concentration of copper sulfate increases from 210 g/L to 225 g/L, the filling effect is good and the sag degree is about 0. However, with the increase in sulfuric acid concentration, the sag increases gradually. When the sulfuric acid concentration is 25–35 g/L, both the sag and copper coating thickness are in a small range. Under appropriate electroplating conditions, a better blind hole filling effect can be obtained. The volume of blind hole has a certain effect on the diffusion and exchange of copper sulfate and sulfuric acid, as well as on the concentration distribution of additives.

Recovery of Metals from Heat-Treated Printed Circuit Boards via an Enhanced Gravity Concentrator and High-Gradient Magnetic Separator

“…Epoxy resin is the adhesive of PCB, and its glass transition and thermal decomposition occur at a high temperature [ 26 , 27 ].The waste PCBs was subjected to heat treatment for the better metal liberation, but thermal decomposition should be avoided due to the potential release of noxious gases [ 28 , 29 , 30 ]. Keeping the heat temperature between the glass transition and thermal decomposition ones is the ideal condition to achieve an improved liberation.…”

A Green and Facile Microvia Filling Method via Printing and Sintering of Cu-Ag Core-Shell Nano-Microparticles

“…The electroplated microvias could obtain satisfactory electrical properties, however, this technique has several drawbacks: (1) The electroplating is a multi-step process composed by exposing, developing, etching, and plating procedures, which are complex and the by-products may cause environment pollution [ 4 ]. (2) For electroplated microvias with large depth/diameter ratio, it is difficult to achieve the “bottom-up” filling mode and voids will form inside the microvias [ 5 ]. As the current density is limited to maintaining stable plating, the efficiency of electroplated microvias with large diameter and depth is low [ 6 ].…”

Special Issue of the Manufacturing Engineering Society 2020 (SIMES-2020)

“…Regarding the specific contributions of the Special Issue in the journal Materials, 17 contributions about cutting-edge advances in different fields of the manufacturing engineering have been collected. In particular, these concern advances and innovations in manufacturing processes [6][7][8][9][10][11]; additive manufacturing and 3D printing [12,13]; sustainable and green manufacturing [14,15]; metrology and quality in manufacturing [16,17]; manufacturing of new materials [18]; manufacturing systems: machines, equipment and tooling [19]; robotics, mechatronics and manufacturing automation [20]; Industry 4.0 [21]; design, modeling and simulation in manufacturing engineering [22]. Figure 2 shows the main topics and their percentages in this journal.…”

“…Concretely, within the topic "Advances and innovations in manufacturing processes", the works are focused on manufacturing processes. Mainly, machining [6][7][8], forming [9], joining [10] and electroplating [11]. In machining, Kubo et al [6] use bio-inspired DNA-based computing for determining surface topography of a dressed grinding wheel; Wood et al [7] analyze the machinability of inconel718 alloy with a porous microstructure produced by laser melting powder bed fusion at higher energy densities; and Navarro-Mas et al [8] compare different parameters to evaluate the delamination produces in the edge trimming of basalt fiber reinforced plastics.…”

“…In joining, Alves et al [10] study attachment of sheets to tube ends made from dissimilar materials with a single stroke. Additionally, in electroplating, Tao et al [11] analyze the effect of copper sulfate and sulfuric acid on the blind hole filling of high-density interconnect (HDI) circuit boards by electroplating.…”